Secret Course 09
From the Super Mario Wiki
The course starts with a ? Block containing a Super Mushroom and a few Brick Blocks with Ninjis on them. The first Bonus Medal is found on the second Brick Block. After this, the next two Bonus Medals are found among three Ninjis on the ground. After this is another Ninji on a Hard Block. The fourth Bonus Medal can be obtained by jumping off this Ninji. There are then two more Ninjis and the fifth and final Bonus Medal, which can be obtained right before the Goal Pole by jumping off the last Ninji.