Saturday daytime for a boy aged 11

I'm looking for someone to hang out with my 11 year old boy every second Saturday during the day while I'm at work. Starting at 11 and finish 6 pm.

This is a very active shift with not much sitting around. He loves to kick a ball, go to the pool, to the city for an adventure, hang out outdoors. He's very easy going, funny and polite and just an overall great kid.

I'd like someone sporty closer to his age.