Has an AFL game ever ended 91-91?
Exactly once. On April 12, 1969, Essendon and Geelong drew 91-91, and no AFL game before or since has ended that way. When it happened it was a scorigami, the first 91-91 in league history.
That makes 91-91 the 3884th most common final score out of 6,649 that have ever occurred in AFL. One point away, 92-91 has happened 6 times and 91-92 has happened never.