Has an AFL game ever ended 90-7?
Exactly once. On September 3, 1898, Fitzroy beat Carlton 90-7, and no AFL game before or since has ended that way. When it happened it was a scorigami, the first 90-7 in league history.
That makes 90-7 the 3836th most common final score out of 6,607 that have ever occurred in AFL. One point away, 91-7 has happened never and 90-8 has happened never.