Seven island has not much to offer in the north there is a trainer tower where you can test your Pokemon against other expert trainers. Also in the south you can capture Unowns in the tanoby chambers. Also this island is home to strong trainers this is a good area to train your Pokemon.
There is no island 9 in either Pokemon FireRed or LeafGreen. Whoever told you this is very off. There are Seven Islands (Sevii Islands)
No legendary resides on the islands a rare Pokemon resides on seven island in the tanoby chambers the Pokemon is unown.
first get them on firered/leafgreen from the seven islands, then migrate them
kanto -- Kanto, with the addition of the Seven Sevii Islands!
8 Island does not exist. Only the sevii islands. There are seven islands in leafgreen and firered. Four of them can only be visited after finishing the game.
Not regions seen in other games, but you can visit some islands that are introduced in the FireRed and LeafGreen games.
The only "passes" that I can recall from Pokemon FireRed are the Tri-Pass, which grants you access to Islands One, Two, and Three, and the Rainbow Pass, which grants you access to Islands One through Seven (the Sevii Islands).
Whirl islands are in the johto region which is not in firered.
Explore, catch pokemon, train your pokemon.
in 4-7 islands
seafoam islands
you cant