It is not possible to get a ninth badge in Pokemon FireRed. You can only get eight badges in Pokemon FireRed.
YES
you have to beat the gyms in the area.
After obtaining the other 7 badges you return to Viridian City and the gym will be open.
The gym leaders have the badges all you need to do is defeat them.
by defeating them in battle
No, you don't. I had 7 badges when i got the tri-pass.
8There are 8 badges, with the elite four after that.Hope this helpsPlease recommend me.
Just like in FireRed/ LeafGreen versions, you must have 7 badges.
you need to beat the 8 gym leaders
You get all the badges from all the gyms
They grant access to Indigo Plateau, where the Elite Four and Pokemon Champion reside.