You have to throw the evil bowser wind up toys at him by running at it-press B-press up and let go where bowser is. Measure the time so you don't miss! I beat that game already :)
EDIT:
oops and i forgot to add --- step on the evil wind up toys first so you can squish them, then you can grab them and throw them.
Just go to this site and it tells you everything:
http://gameolosophy.com/games/gaming-on-the-go/
if it's the ds one then no there is no world nine but if your talking about the wii the yes you unlock it when you finish bowsers giant castle in world
Defeat bowser at the end of bowsers galaxy generator.
You have to complete the world five castle as mini mario.
if you mean new super Mario bros, then you beat world 6 castle when you are mini Mario.
beat the castle in world 1
it is not stars it is a world
In super mario? Ahem... You do all of the tasks before it.
All you have to do is go to the world 2 castle and beat the boss with mini Mario
Whoa. There is Alot. Donkey Kong Mario Bros. Super Mario Bros. Super Mario Bros. Special BROS Super Mario Bros. USA (Super Mario Bros. 2 in America) Super Mario World Super Mario Kart Super Mario RPG Super Mario The lost levels (Super Mario Bros. 2 in japan) Mario's Early Years: Preschool Fun Mario Teaches Typing Super Mario 64 Super Mario Sunshine Super Mario Galaxy Super Mario RPG 2! (Mario & Luigi: Partners in time in America) NEW Super Mario Bros. Super Mario RPG 3! (Mario & Luigi: Bowsers inside story in America) NEW Super Mario Bros. Wii Super Mario Galaxy 2
It is very easy. Just defeat bowser in 1-castle.
Well, if you are talking about New Super Mario Bros. for DS, you go the final castle in world 5 where you fight Petey Pirhana. Well, the thing is that you need to defeat him WHILE you are mini Mario or Luigi.
For world 4 complete world 2 castle defeat the white thing being mini Mario and for world 7 do the same except on world 5 castle!