Example from the IAHSAA
Q 15: We have a student attending our school this fall whose parents have been divorced for several years. The student has lived with his biological mother in our school district (CR WASH) for many years. The student now wants to go live with his biological father in ANKENY and attend high school at CENTENNIAL. Will he have immediate eligibility there?
A: Unless there has been a change in the marital status of the student’s biological mother, or a change in the divorce decree granting the biological father custody, the student will be ineligible for 90 school days at the varsity level at CENTENNIAL High School.
In this case, a likely change in custody and he plays right away at AC. No way he leaves CRW if he would have to sit at AC.