Title IX is essentially an Act of Congress passed in 1972, as a follow up to the Civil Rights Act of 1964. In terms of "interpretation," interpreting laws is the role of the courts (not the role of elected officials as Ted Cruz implies).
Courts traditionally interpret laws by examining legislative intent -- the intent of the legislative body that passed the law, not the body that is currently sitting. Regardless of the source of the Fourth Circuit interpretation, its interpretation is legally binding on all lesser courts within its jurisdictional area.
The only way for the matter to go to the Supreme Court is by writ of certiorari, and unless the Supreme Court sees a conflict between the circuits, it will deny certiorari and let the ruling stand.
Which means that the religious nuts are going to have to try to get a circuit level ruling in their favor out of another circuit. Their best hope of doing this is out of the Fifth Circuit, since it is traditionally conservative and Mississippi already has a law in place, or the Sixth Circuit, which is why they are pushing so hard for discriminatory laws in Tennessee. They already failed in Georgia, and Florida and Alabama have too strong military and business communities, so I doubt we will see any fights like this in the Eleventh Circuit.
The Ninth and Tenth Circuits in the west are traditionally liberal, as are the First, Second and Third Circuits in the northeast.
This leaves the Eighth Circuit as their only remaining road to the Supreme Court, which is why they are fighting for discriminatory laws in Arkansas, Missouri, Minnesota and the Dakotas.
Aside from judicial interpretation, the only other way for the Religicans to topple or rewrite Title IX is through another Act of Congress -- which is why we should all be watching the next election very carefully. Trump tells people what they want to hear, which means he will follow the majority in Congress if he is elected. We know what Cruz will do.
I pray for a democratic win, not only for the White House, but for a majority in Congress as well.