Don't worry about wisdom teeth, and no need to take them out before the academy. In fact, they are best removed when the dentist makes that diagnosis and not before. It is a medical decision. The dental care at USCGA is pretty good and they will advice each cadet on what they see in the annual dental x-rays.
Yes, if your wisdom teeth haven't emerged by 2/c junior year, they will send you off base to the oral surgeon and have them removed. Many cadets go through this procedure. If they have emerged, the USCGA dentist will remove them.
Tip: Tricare (Mil Insurance) pays for the dental work. However, if you want additional long lasting sedation from the oral surgeon, just let your kid know and for a slight upcharge they may get an Exparel shot which makes the 72 hours after surgery much better. Good to schedule the removal on a Thursday if possible, then you can visit that weekend if you want because the cadet will be SIQ (Sick in Quarters) for a few days an as a 2/c can go off base and usually hang with you in a hotel. By 2/c year, Chase hall gets a little old, especially when you are SIQ.
Bottom line, it is usually not a pre-admission issue, and just discuss your wisdom teeth situation with the dentist during one of your twice a year visits.
If you have questions, the USCGA dental clinic is the controlling authority on this, you can give them a call.