That's not how it works at all. There are very clear guidelines and they are published. It's not my specific field of law but I've read them and so have thousands of lawyers. The USTA is next to irrelevant and that's if they actually wanted to try which they don't and with good reason.
I don't know what you mean by 'appeal.' Here's the relevant info from the US CDC:
Categories of noncitizen nonimmigrants that meet the criteria for an exception under the Proclamation and CDC’s Amended Order include:
- Persons on diplomatic or official foreign government travel
- Children under 18 years of age
- Persons with documented medical contraindications to receiving a COVID-19 vaccine
- Participants in certain COVID-19 vaccine trials
- Persons issued a humanitarian or emergency exception
- Persons with valid visas [excluding B-1 (business) or B-2 (tourism) visas] who are citizens of a foreign country with limited COVID-19 vaccine availability (See list for updates effective June 28, 2022)
- Members of the U.S. Armed Forces or their spouses or children (under 18 years of age)
- Sea crew members traveling with to a C-1 and D nonimmigrant visa
- Persons whose entry would be in the national interest, as determined by the Secretary of State, Secretary of Transportation, or Secretary of Homeland Security (or their designees)
As you can see, only the last provision offers any help even theoretically and it's unlikely in the extreme.
Unlike in most other comparable countries, there's not even a Minister of Sport in the US. You would need the Secretary of State, Transportation or Homeland Security to actually go to bat for a tennis player. That's absurd on its face and of course there's not a single instance of them even taking a slight interest in more popular sports with people in similar situations.