“Hey! My name is 9-Volt! I'm the grade-schooler gone old school!”
9-Volt is a major human character in the WarioWare series. He is a Nintendo fan, he collects everything about this company, and loves to play video games. 9-Volt lives with his mother, 5-Volt, and his pet Fronk in their house in Diamond City and attends Diamond Elementary. He debuts in WarioWare, Inc.: Mega Microgame$! as one of Wario's friends who helps him produce microgames.
 WarioWare, Inc.: Mega Microgame$!
Firstly, 9-Volt could be seen in the intro of WarioWare, Inc.: Mega Microgame$!, where he is called by Wario to join his "company" WarioWare, Inc. and to produce microgames for his upcoming game. Like Wario's other friends in Diamond City, 9-Volt agrees.
In 9-Volt's own story, the school is out and he skates home with his high-tech skateboard, SK8. At the house, 9-Volt gets into his room and plays with his mixing console. 9-Volt says "Hello" a few times and with the help of the machine he imitates the voice of Jimmy T. or at least a similar voice while saying it. 9-Volt's oversized Game Boy answers him with "OK". Then 9-Volt makes music with the mixing console and spins records on it. Some kind of grabber comes out of the Game Boy and pops an over-sized cartridge into it.
Later, while 9-Volt still spins records, Ken the Reporter appears and announces that the Game Boy Advance SP is on sale in stores. Quickly, he leaves the house and his skateboard transforms into a hoverboard. With that, 9-Volt hurries to the next store to purchase the new handheld.
9-Volt also makes a short appearance in the ending story of the game, where Wario states to his employees in the WarioWare headquarters that they wouldn't get anything of the money he earns with the game he and his friends make and then he escapes. 9-Volt is in shock, but like the other employees except for Mona, he didn't chase after Wario.
9-Volt is featured in four unlockable minigames in WarioWare, Inc.: Mega Microgame$!. In SkatingBoard, he appears as the protagonist of the game and has to avoid obstacles and red birds with his skateboard. In the two-player minigame VS Chicken Race, 9-Volt is the character of the player who has to use , while the other player's character is a Fronk, possibly his pet. 9-Volt also makes an appearance in the minigame taken from Mario Paint, Fly Swatter, where the Spiny appearing in the congratulations sequence has been replaced by him. The minigame Paper Plane features 9-Volt as one of the characters looking through a window and telling the current flight time.
 WarioWare, Inc.: Mega Party Game$!
In WarioWare, Inc.: Mega Party Game$!, 9-Volt hosts a television show called Super Show. There, he uses a mixing console again and a Game Boy Advance with arms and legs that states "OK" in a similar way to the Game Boy in the prior game. After 9-Volt's entrance, Kat and Ana followed.
9-Volt is one of the ten selectable characters in the multiplayer games.
 WarioWare: Twisted!
In the intro of WarioWare: Twisted!, 9-Volt comes along with Mona to Dr. Crygor's Lab. There, Dr. Crygor tries to fix Wario's broken Game Boy Advance with his invention, the Gravitator. But it has no buttons anymore after the repairing, instead of that the player has to move the system to move the character in the game. 9-Volt and Mona try it out and enjoy it. Wario gets the idea to make a new WarioWare game involving this style of gameplay.
9-Volt is shown to be a troublemaker at school in this game. In his own story, a new student named 18-Volt came into his class. On his first day at Diamond Elementary, the teacher asks 18-Volt what his hobby is, to which he responds by taking out his boom box and playing loud Rock 'n Roll music.
18-Volt got in trouble for this and after school he heads for his house broken-hearted. However, 9-Volt stops him and states that he enjoys his music. The two of them become fast friends and 9-Volt invites 18-Volt over to his house. When they got there, 18-Volt is ecstatic to see that 9-Volt has a Nintendo Entertainment System and the duo spends a lot of time on playing on the system. Eventually, his mother, 5-Volt tells 9-Volt and his new friend to cease.
At night, when 9-Volt has to sleep, he furtively plays with his Game Boy Advance SP under the bedspread, but 5-Volt catches him.
 WarioWare: Touched!
In WarioWare: Touched!, 9-Volt and 18-Volt go to the Toy Express to get a copy of the coveted, new Nintendo GameCube game, 36-Volt Man. 9-Volt snatches one and shows it happily to 18-Volt, who is carrying his boom box on his shoulder. Curious about their new game, the two friends quickly return to 9-Volt's house, in which he uses his SK8 to reach it. On their way, they pass the alien Orbulon who is running after his flying spaceship.
At the house, 9-Volt and 18-Volt play far into the night and reign victorious in the game. To celebrate their success, 9-Volt spins records again, with 18-Volt dancing behind him and his Nintendo consoles in front of him. 9-Volt's mixing console features moving Mario and Luigi figurines, but it got so late that the two gamers fall asleep.
In the morning, when they wake up, it's already 9 o' clock. 9-Volt and 18-Volt are shocked about the fact that they're late and rush to school.
 WarioWare: Smooth Moves
9-Volt is visited by 18-Volt again in WarioWare: Smooth Moves. There, he showed a Game & Watch handheld console to his tall friend and plays with it. 18-Volt mistakes it for a Nintendo DS Lite at first. He wants to see more of the console and gropes it, but 9-Volt still has the console in his hands and informs him that he is still playing, but he couldn't wait and the Game & Watch breaks in two halves. He gets furious and commands 18-Volt to leave his house.
Now, 18-Volt has a bad conscience and tries to find a new Game & Watch for his friend. He first looks in Toy Express, but they didn't have what he desires. After leaving the store, 18-Volt notices another store where some gamers lineup. He got into the store and the owner of the shop, Shop Manager Iwata, coincidentally has the searched Game & Watch on offer. 18-Volt reaches for it, but surprisingly 9-Volt does the same. The friends face each other and they both excuse each other for their mistakes. 9-Volt tells 18-Volt that he will always be his P2 (Player 2) and all goes well after that.
 WarioWare: D.I.Y.
In WarioWare: D.I.Y., a game called Super 9-Volt shows up in 9-Volt's stage. It's a spoof of Super Mario Bros. and stars 9-Volt rather than Mario. 9-Volt, skateboarding, hits a Question Block shaped like a Famicom cartridge every time a microgame is won.
9-Volt, along with Mona, Jimmy T., Orbulon, and Ashley apparently left WarioWare, Inc. to work for Diamond Software in this game. Although, the reason they switch companies is unknown, various residents of Diamond City consider possibilities in the DIY Forums feature of the game.
18-Volt, who continues working for Wario, appears to view 9-Volt as a rival after his departure, as suggested by his role as a boss in his game (as well as their interaction after the boss game is completed) and his greeting to the player where he insists that he works at "twice the power as that other guy you might be thinking of".
 Game & Wario
9-Volt appears in the Wii U game, Game & Wario. He hosts the minigame "Gamer", that stars him with his Game Boy Micro-like console, playing microgames. As he was supposed to sleep, his mother often drops by his bedroom. If 5-Volt finds out 9-Volt is playing video-games during his bedtime, he is scolded by her and the player loses. On his minigame's title screen, 9-Volt is depicted as having red hair; this is also the first time he is seen without his helmet.
He also appears in the Bowling minigame, as a bowling pin (like most other characters in the game).
9-Volt comes with his own set of microgames in all games of the WarioWare series. Between WarioWare: Twisted! and WarioWare: D.I.Y., the games are always provided by both him and 18-Volt. However, it isn't known how much he shares in the creation of the games. For example, in WarioWare: Touched! 9-Volt says "our games", but in WarioWare: Twisted! he just speaks about "my games" in the character select menu, plus 18-Volt isn't even mentioned by name in the menu.
The microgames are based on products of Nintendo, mainly on game software and hardware, but also on merchandise from the time before Nintendo became popular as a video game company. Microgames based on the Mario series are featured in every WarioWare game.
For WarioWare, Inc.: Mega Microgame$!, 9-Volt creates microgames of the Nintendo Classics genre. The games involve various Nintendo products from the 1960s up to the 1990s. WarioWare, Inc.: Mega Party Game$! also feature his Nintendo microgames, plus a multiplayer game made by him, Card-e Cards, which refers to a Nintendo product as well, in this case, the e-Reader.
In WarioWare: Twisted!, the microgame set of 9-Volt and 18-Volt is called Spintendo Classics. As an exception all microgames are only based on Nintendo Entertainment System games in this game. While the microgames of most of the other developers involve a particular style of gameplay per developer, the microgames of him and him require all kinds of spin techniques.
In WarioWare: Touched!, the name of 9-Volt and 18-Volt's set of microgames is Retro Action. The choice of Nintendo products is much more versatile than in the prior game again. Also newer products from the 21st century are featured. The microgames include all kinds of ways of using and also the application of the microphone, while most other microgame sets involve a particular technique again.
In WarioWare: Smooth Moves, 9-Volt and 18-Volt's set of microgames involve all possible forms. Considerably more microgames are based on more recent Nintendo products. An example is Brain Age, which is based on the Nintendo DS game Brain Age: Train Your Brain in Minutes a Day!
In WarioWare: D.I.Y., 9-Volt returns to his original role by going solo, while his friend 18-Volt is granted with his own microgames in WarioWare: D.I.Y. Showcase. Despite this, their microgame stages are both Nintendo themed. Akin to WarioWare: Smooth Moves, 9-Volt's microgames adapt to more recent Nintendo products such as Wii Fit.
 Official Profiles and Statistics
 Profile Information from WarioWare, Inc.: Mega Party Game$!
 Website Bio from WarioWare: Touched!
Old-skool fanboy finds a soulmate in new classmate 18-Volt. Together, they serve up microgames inspired by classic Nintendo games.
 Super Smash Bros. Brawl Sticker Information