I'm not sure how much a personal Twitter account will do for you. The people you are trying to reach — coaches — aren't just randomly on Twitter looking for people who had a great weekend. And once you have their attention, likely you are communicating on a personal level via texts rather than in a public way like Twitter.
I can see retweeting stuff from Perfect Game, but again, the people following you are likely to be people know, rather than people who want to know about you, if that makes sense.
And just because someone needs to say it. Be careful of what you tweet, and what you retweet, both for you and for your son. You may have heard here in Iowa that when Carson King was raising $3 million for a children's hospital, people dug up racist tweets from when he was 16 and published them. These things don't go away and what seems funny or innocuous right now can do a lot of damage down the road.