This would be a REALLY BAD IDEA.
From the outset let me say that I raised daughters, all three sport athletes, with numerous coaches and never had this experience. While I abhor the conduct of the coach mentioned, we should not make MSHSAA a mandated reporter other than to the school district responsible for the coach.
MSHSAA is a member organization which has difficulty fulfilling its present obligations to its members. Why saddle them with more? Why should school districts A-Y be responsible for an employee in district Z? They should not, and therefore not be liable on any grounds for that employee. We have waaaaay too much bureaucratic BS to deal with as is.
The answer to this is really simple for the parents. Send a letter to every Board member, every administrator in the building, the chief of police and/or county sheriff, DESE, and the teacher outlining your concerns with exhibits. Emphasize that you expect things done in hours and days, not weeks and months.
Or you could resort to the Mid 1900's method where dad would pick up the phone, call the individual and say, "Look you sonofabitch, we know what you did to our daughter. Get your gear packed and your resignation in or me and my friends are going to come over there and slit your bag and run your (effing) leg through it!"