Has there ever been a 9–0 in the Brasileirão?

Yes, 1 time.

The only time: February 19, 1984, Vasco da Gama beat Tuna Luso (Vasco da Gama 9–0 Tuna Luso).

Nearby scores

1. 10–0 Never
2. 10–1 1 time
3. 9–0 1 time
4. 9–1 Never
5. 8–0 5 times
6. 8–1 3 times