The problem there is that boys/men's sports are more popular, and they have an easier time raising funds privately. It's one thing to have equal amounts of public funds for both, it's something different to make sure both are funded equally. I don't know enough about it, but I wouldn't be surprised if someone tried using title 9 to acquire public funds for girls sports to match the public as well as private funds that boys sports got.
The entire reason we don't treat gender dysphoria as a mental illness anymore is the fact that democrats realized the political capital they could gain by treating people with the disorder as a protected class. Of course it is going to be abused.
Thank goodness we don't have human rights tribunals like in Canada, otherwise we would have minority women being forced to wax the penis and scrotum of a trans woman. The entire thing is insane on its face, and the leftists (who are still convinced they are liberal or progressive) are just daring us to push them to show how far they will go with their virtue signalling, supporting the craziest policies. We laugh about age fluidity now, tomorrow we'll be forced to accept that it's real or be cancelled.