I ref a lot of soccer games and a 9 year old playing in a competitive game with 5 year olds is rather dangerous. Considering how size the alleged 9 year old probably has over the younger kids, he could really hurt someone. There's a lot of free balls, especially in little kid soccer where no one can posses it, so there's a lot of times where two opposing players are going for the ball and they don't always know how to control their bodies yet and collide. The potential risk for injury alone along with the obvious bending of the rules is a very poor lack of judgment by the coaches. Not only is it in the best interests of the other players to protect them, but also to teach all the kids a good lesson about life.