You get you 8th badge from Blackthorn City's Dragon Type Gym. Her name is Clair, and she owns a Lvl. 38 Gyarados (girl), a Lvl. 41 Kingdra ( girl), and two Lvl. 38 Dragonairs( both girls). I suggest using the super effective electric, ice, and dragon type moves. When you win, you'll get a rising badge. It lets all traded Pokemon obey you, and you can use the move waterfall to scale them when not battling.
blackthorn city
Go to the forth gym!
You will have to defeat Bugsy in Azalea Town. He has bug-type pokemon.
In Mahogany town right from Etrack city
it is bugsy the bug type leader
It is your rival from Pokemon fire red and leaf green versions.
you have to get the cianwood gym badge and the olivine gym badge
It is not possible to get a ninth badge in Pokemon FireRed. You can only get eight badges in Pokemon FireRed.
you get it in ilex forest after you get your 2 badge! hope this helps
go to the sprout tower in the town where you get the first badge at night.
in Goldenrod city
It is in Ecrutuk city the leader is morty who uses ghost type Pokemon