Then your teacher needs a kick in the a$$! I would politely bring it up with your him (don't tell him what I said - he may get his back up). Planers are quite loud and everyone in the vicinity should have proper hearing protection. If he doesn't look into it, go over his head. You may want to get your parents involved at that point. I assume the school at least provides safety glasses? If not, he should then receive a kick in the jewels.
You should have something like this
as a minimum:
Professional Hearing Protection | Canadian Tire
Preferably in combination with something like this:
Ear Plugs, 80 Pairs | Canadian Tire
Whatever is used should be NIOSH and/or CSA-approved.
I just can't believe that this isn't being provided by your school. If the school is not obligated to provide such equipment (and I'd be surprised if they weren't) - get your own. Even if nobody else in your class wears it, you should. I'll put it this way - an employer would be charged, if an inspector found employees working in a noisy environment without such equipment.