Smars is right, your player already has high rebound for a guard. More rebound would reduce his cap and increase his salary.
Glad to read you'll keep on training IS. The goal will depend on how fast he grows. If 14 IS comes fast, why not reaching 15 or 16 IS.
I propose you to finish with training outside defense because it'll make him play point guard. Also IS will increase really slower when he will be 25 yo, because he is quite small