Hmm. I'm somewhat like your son. I consider myself to be ambidextrous in a lot of ways (not all ways, though). For example, I can play racquet sports with two hands. This gives me a pretty big advantage in the amount of court I can cover from any given spot. I can write with both hands, which has obvious advantages.
Have you asked your son if a racquet/bat/pencil/whatever feels comfortable in both hands? This doesn't mean that he can easily write or hit a ball with both hands automatically, but that he feels comfortable using both hands and could learn to use both in a variety of situations.
