In Saffron City, the top right there are two gym looking buildings. The one on the right, I believe is the gym.
It is not possible to get a ninth badge in Pokemon FireRed. You can only get eight badges in Pokemon FireRed.
The Rainbow Badge
viridian city
spoon!
leaf
The 7th badge.
island? the fourth badge is in celadon
Saffron city.
The 4th pokemon badge is given by Erika the Celadon City Gym Leader.
The 7th badge
The boulder badge, the cascade badge, the thunder badge, the rainbow badge, the soul badge, the marsh badge, the volcano badge and the earth badge.
First beat team rocket at the Pokemon tower and the game corner and then get the 5th badge now you should be able to go inside silph co.