I never thought I had a problem with my wisdom teeth. In fact, 3 out of the 4 had come in and never caused a problem.
One day, when I was about 23yrs old, the one that didn't come out started to come out and hurt. I thought, oh great, here it comes. I went to an oral surgeon who did a panoramic x-ray.
They discovered a massive tumor in my jaw. It had eaten away at my jawbone over the years and was sitting on a nerve. The guy told me he'd have to remove the tooth and the tumor and, when he did, he would sever my facial nerve and I'd loose feeling in my lower lip and lower back of my teeth/jaw/face. He said it could be permanent. He recommended I put off law school because I'd need OT to learn how to speak again and function without the use of my lower lip. Oh, and don't worry, he said, 95% of the time, it's not cancer.
The surgery involved returning to his office every single week to have the wound packed with anti-bacterial gauze. I was horrified.
Thankfully, I got a 2nd opinion at a world-class hospital where a doctor there helped me. They removed all 4 wisdom teeth since, despite them being "out", they were still impacted and causing problems I couldn't yet detect from the outside.
For a year, I had a rubber hose sewn into my face where the jaw bone was growing back over the nerve. A year after my 1st surgery, they removed the tumor and saved my nerve. And, it wasn't cancer.
I still have to go back every 18mo for panoramic x-rays because they can grow back.
Wisdom teeth are nothing to mess around with. They're not "just teeth" and they can present bigger issues than shifting teeth.
When you finally have a problem, you have a BIG PROBLEM. So, waiting until there is a problem could be setting your son up for a horrific experience. If only MY dentist or MY orthodontist had the foresight to do a panoramic x-ray and see what was going on in there, maybe I wouldn't have had to go through what I did. I guess back then they had less information about this kind of stuff.
If you're hesitant, get a 2nd opinion. I know I'm glad I did. That 1st guy was going to just hack at my teeth and sever my nerve. I'm so thankful I got the 2nd opinion.
Good luck.