Just a reminder that the responses that will be forthcoming will be tailored to a 9 year old. A 9 year old will have a lot of changes to his mobility, balance, and choreography in short spurts as time goes on. In other words, he's growing and developing things that make consistency difficult sometimes. So just be aware of what works today or this week, may not be there a couple of months from now.
Also, environmental conditions like the surface that he's standing on while pitching has a tremendous impact and influence on his ability to take what's give here and actually work with it. So, don't be too harsh or judgmental on the flip side of trying to apply our suggestions and observations. Now I'm not suggesting that you will - but just be reserved during this entire process.