Has an AFL game ever ended 109-90?
Exactly once. On July 28, 1990, Melbourne beat Fitzroy 109-90, and no AFL game before or since has ended that way. When it happened it was a scorigami, the first 109-90 in league history.
That makes 109-90 the 3884th most common final score out of 6,649 that have ever occurred in AFL. One point away, 110-90 has happened 4 times and 109-91 has happened 4 times.