Ojai has produced very good players recently. Kallim Stewart, a highly touted junior, will join Cal next season and there has been a lot of buzz about him.
If you absolutely don't want your son to leave California then I think Ojai would be a decent choice. But I mean, if you are sending your kid to a boarding school, you might as well get him the best training possible, since he will be living away from home in any case. With that said, institutions such as Newk's, Saddlebrook, Bolletieri, Evert are all reknown academies, which have produced the top juniors for the past decade.
Take care and good luck!
