He arguably has standing to sue for defamation. Also injurious falsehood (that's an old one, but still valid in Florida).
As far as the defamation case, he may also claim that since it goes to his livelihood and business, it is defamation per se (making the proof of damages far less stringent).
But I also want to raise the possibility of a tortious interference w/ business relationship claim. Whatever findings the NCAA made, including their alleged attempts to have UM (and its student athletes) disassociate itself from Ruiz, that arguably was with knowledge of Ruiz's business relationships w/ UM student athletes. That could be problematic for the NCAA (and a great basis for venue in Miami).