World 9-1 (New Super Mario Bros. Wii)
From the Super Mario Wiki
World 9-1 is the first level of World 9 from New Super Mario Bros. Wii. This level is sky-themed and is unlocked by collecting all of the Star Coins in World 1. The level uses the background of World 1 and plays the athletic theme. Like all levels in World 9, there is no midway point.
World 9-1 is an athletic level with a layout similar to that of World 7-1. There are a number of spinning rectangle platforms around the level. Also appearing is a giant spinning L-shaped platform. Koopa Paratroopas are the main enemy in this stage along with a number of regular Koopa Troopas.