I have a 12 year old and an 8 year old sharing an iPad, and yes, they can't use it in their room.
But I did lock it down fairly well (unless they have figured out my passcode). I used most of the instructions here:
https://www.howtogeek.com/177366/how-to-lock-down-your-ipad-or-iphone-for-kids/
At one point they couldn't even YouTube... I had to turn it on so they can see those instructional videos on how to bleed brakes.
