I coach with a class D soccer coaching license (I will give it to organized soccer leagues, they are very strict on coaching requirements and you need the license to coach), which allows me to coach kids up to 13. No headers allowed at any level up to that age, and if a purposeful header is done in a game it's a foul. Incidental contact with the head happens anyway, especially for young players when the ball can go flying in random directions, but any head contact results in an immediate stop in play, that player removed from the field until evaluated and cleared by a medical professional (or sometimes coach if no medical is available on site, but then you have to follow the protocol).
Rec leagues are typically their own beast, though, especially if they aren't sanctioned by IYSA.