Ultimately you cannot and it would be irresponsible to do so. It is not "your" chromebook it is the school's. In this scenario you'll have to put up with the restrictions or better yet get your own device. If money is tight I recommend going to e waste facilities.

Now I do understand this energy and had a few run ins with things like this in my youth.

If you really want to go through with this, which again, is not right and will get you into trouble.

I recommend looking into chromebook powerwashing. it will reset lots of firmware to stock.

There's not going back and it will completely wipe the system.

Like the other person said, talk to your teacher. Even if you don't get an assignment or something, just say that you want to learn more about Linux/Bash/Python etc, so all you need the admin to do is enable the Linux dev environment, which is just four taps (Settings > Advanced > Developers > Linux).

Talk to your computer science teacher and ask for a terminal oriented assignment.

With this task in hand open a request for terminal access with the IT department.