Press the minus button then press 2 on any world.
Super Mario World
Press L and R then press A to begin and you should have it when you enter the world you were in when you quit
no
skills
no
no there is not
there is only a world 8 unless you are talking about the secret world which you can enter by pressing LRLRXXYY (you have to beat the game first)
there is no world 9 in new super Mario bros. there is one in super Mario bros 3 though
World 9 does not exist in New Super Mario Bros. DS
Technically, Super Mario World is already Super Mario Bros. 4. In fact, its working title before being released was "Super Mario World: Super Mario Bros. 4."
Yes
No.