Wario Land: Super Mario Land 3 is a 1994 platform game developed and published by Nintendo for the Game Boy. It is part of the Wario series and a sequel to 1992’s Super Mario Land 2: 6 Golden Coins. The story follows Wario traveling to a distant island to steal and sell a valuable statue to purchase his own castle out of envy for Mario’s. The player traverses themed zones consisting of levels, each of which is scattered with collectible coins that can be used to purchase items that aid the player in progressing through stages.
Where is the treasure room in level 9 ?

How can you recover a treasure that’s been lost?
How do you reach the treasure chest in level 11?

Information was found in Nintendo Power volume 59, page 72.