I'd hold out. Kids bodies aren't fully developed. I kinda look at it as teaching a 12 year old to throw a curveball. Sure he'll dominate at the time, but all that abuse on his arm and having Tommy John's surgery before he's 20 isn't worth it. There's a reason football games are only played once a week, the body needs to recover, especially a developing kid's body.
Is there any reason why you would go with the rec league over the school? My school would start teaching the plays in middle school that we ran in high school, so we had them down after 5 years of running them.