Has an AFL game ever ended 48-9?
Exactly once. On May 27, 1899, Essendon beat Carlton 48-9, and no AFL game before or since has ended that way. When it happened it was a scorigami, the first 48-9 in league history.
That makes 48-9 the 3836th most common final score out of 6,607 that have ever occurred in AFL. One point away, 49-9 has happened never and 48-10 has happened never.