8 players should be enough ...
PG: A, A, A
SG: B, B, B
SF: C, F, F
PF: D, G, G
C: E, H, H
In case of injury (either player A or B), players F G H will play at that position by rotation. Coach will make that decision and training minutes will be affected.
Therefore, there is no need to use 9 players even if there would be an injured player.