1. The pitch back thing...I bought a $5 personal trampoline at a yard sale, hung it up on a tree and my son bounced balls off of there for 5 years, it was awesome!
2. 15u is a step up but only about 20% of the teams are a big deal. I'm sure just like in GA you can find a lower level team in CA to start him on. We have teams at 15u that run from 95mph pitching to 60mph pitching, no lie. We have levels, Majors, AAA, AA, A...the majors full up quickly but you can always find room on the other teams. We have a local youth board for travel ball, maybe you guys have one too? we can look up team tryouts and see when people post that they need players. There is even a sandlot type of team where they gather 15 kids for a tourney and tell them all to wear yellow tshirts and pay $20 to play. You can find him a spot I'm sure!