List of ninth degree black belt national champions?
The question offers several challenges:
In what style of martial arts? There are several dozen very large
national organizations promoting various competitions as national
National Champions that are 9th degree black belts are going to be
pretty small group, as most practitioners don't compete much after
they reach 6th or 7th degree (in my style you would be in your 60's
before reaching the rank of 9th degree).