Has an AFL game ever ended 91-55?
It has. 91-55 has been a AFL final 3 times in 16,622 games. The first was Carlton beat Fitzroy on June 24, 1972; the latest was GWS beat Sydney on September 10, 2016.
That makes 91-55 the 1534th most common final score out of 6,607 that have ever occurred in AFL. One point away, 92-55 has happened 5 times and 91-56 has happened 2 times. At one point the score disappeared for 41 years, between 1975 and 2016.