Always_Ask_Questions,
Lots of great suggestions. The whitelist filter is a particularly good idea for kids – Google Family Link can do that on a Chromebook, for example. Just make sure to disable guest browsing and restrict logins to preset authorized accounts only. I would also add rules that devices should be used only in public spaces (dining room, living room) and not in bedrooms. And yes, if the child is defeating your filters, then an escalating tit for tat battle that requires the parent to become more seasoned than a NSA network engineer is not the solution.