Has an AFL game ever ended 15-9?
Exactly once. On May 24, 1899, Essendon beat Sydney 15-9, and no AFL game before or since has ended that way. When it happened it was a scorigami, the first 15-9 in league history.
That makes 15-9 the 3884th most common final score out of 6,649 that have ever occurred in AFL. One point away, 16-9 has happened never and 15-10 has happened 1 times.