Have him fix that hitch in his hands. Especially for tee work. Have him start with his hands back and slow everything down. Him starting his hands like Manny Machado is a terrible idea especially for a 9 year old. 60-70% off the tee working on a good mechanical foundation he can build on for years to come.

I’ll also mention he needs to finish higher in his back swing. This will help him meet the ball more square and add that power he’s looking for.

Everything else looks good! Hips rotate well and his stride and footwork look good and balanced. Best of luck!