Does your player know how to stop on both sides? Sounds silly but many kids get lazy and don't properly utilize their edges resulting in lack of control during games.
If you notice your player skating with a wide stride, remind them to bring their skates all the way under their nose on the recovery.
This is the drill to learn how to properly balance on your edges without shoulders coming forward.
The Tick Drill exaggerates keeping the skates low to the ground.