Same at the HS my kids play. We had several young men who played AAU basketball and were also very good soccer players. Soccer coach would not allow players to tryout until basketball season was over. Too bad. None of the players played hoops ever again. High School League and District Office confirmed that no such rule exists on the state or our district level. It was the AD and the individual coaches.
Also have seen High School Football coach turn terrific kickers away because they play club ball and cannot attend every team practice. Not just kicking practice or special teams but they had to be at all practices. All I can say, Coach, way to shoot yourself in the foot.