To reach Island 4 - 6 (and 7), you need the National Dex from Prof. Oak. This Dex is obtainable after beating the Elite Four and having at least 60 different kinds of Pokémon.
Now, after receiving the National Dex from Prof. Oak, go back to Island 1 (Bill will be at the Cinnabar Island's PokéCenter if you're still in Kanto and need to have a transport to the Islands). Now go inside Island's 1 Pokémon Center and talk to Celio (the guy with his big machine). He will now open a cave in the north.
In this cave the Ruby Gem can be found (make sure you have a Pokémon with you who knows Strength). Return it to Celio and he will give you a Rainbow Pass, which gives access to Island 4 - 7.
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You can catch either Lugia or Ho_Ho
on cinnabar island
its on birth island
On cinnabar island
There is no island 9 in either Pokemon FireRed or LeafGreen. Whoever told you this is very off. There are Seven Islands (Sevii Islands)
its to the left of the pokemon gym on cinnibar island
Growlithe is found in the Pokemon Mansion on Cinnabar Island in Pokemon Firered.
on cinnabar island
Beat the pokemon league.
There no Mew in firered.
you can get deoxys at birth island
in 1 island Pokemon center
On Cinnabar Island
its on birth island
On Birth Island
On cinnabar island
island 3
There is no island 9.