You recieve the sixth badge after defeating Sabrina in the Saffron City gym.
Saffron city.
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Saffron city.
You first need to beat Giovanni at Silph co which is in saffron city once you do that you can go into the gym and receive your sixth badge from Sabrina.
Fight the seventh gym on Cinnabar Island. Then fight the eighth gym at Virirdian City.
You can only get the Sixth Badge from the Sixth gym leader. After defeating the Sixth gym leader, the gym leader will give you the Sixth Badge.
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
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.
The 7th badge.
island? the fourth badge is in celadon