That's great. My niece who just turned ten is in her second year of competitive swimming and so far has beaten all other nine year olds in this area in all four of her strokes. It's amazing watching someone that young being able to "master" four strokes (free, back, breast and butterfly) and win her 100 meter IM by a length of a pool.
BTW, for her recent birthday, I emailed Summer Sanders' agent to try and get an autographed photo from her for my niece as kind of a motivational tool. However, I never heard back from the agent or Summer. Oh well.
Again, great job by your son.