As much as I love Google (not even a little, my love for that company is negative and becoming more negative per second) I would love to run far far away from it. Here's another ball and chain I need to break.
Where can I find a simple parental control access system for my phone and or computer that I allow my kids to use?
No, not really.
I have a whole complex setup including unique profiles and auth with unique limitations per user on services, like what books are available on the eBook server, what shows/movies they can see, even which block list is applied for DNS.
But things like app restrictions on a tablet are entirely manual. I kiosked off and will manually install via adb.
There isnt really an equivalent single tool I'm aware of.