If the player is in control and the coach requests it, grant it.
Reminds me of the time I was coaching my 5th grader (who is now college freshman) ...We were a solid and fundamental team for our age...our team was ahead in a gam but we were beginning to play very erratic. The ball is being passed around the perimeter and I'm requesting time out...and as it gets to my best shooter, about the time the whistle blows to grant it, she's putting up a 3...swish! No shot...time out before the shot! Her Dad was so pissed at me!
But not as mad as the 2nd time it happened in that game about 2 minutes later!
I finally told him I didn't give a damn about his daughter's PPG...I'm trying to teach these kids BBIQ and to understand game/clock management and we didn't need 3s at that point. Poor shot selection was allowing our opponent to get back in the game.