How do I delete Minecraft and Youtube (temorarily)

[frazzledmumoftwo]

Problems with DS aged 9 over school work not being done, and general over difficulties in behaviour.

I would like to be able to do the following, ideally without causing any permanent loss of the game or the "worlds" saved.

On our MacBook Pro
Temporarily uninstall Minecraft (ideally without having to pay another £15+ to repurchase it later, and ideally not deleting data)
Permanently block Youtube Minecraft videos

On our iPad
Ditto - but I think this version of Minecraft was cheaper to buy?
Again, permanently block Youtube Minecraft videos

I'm ok-ish on computers, but not as good as DS. Would anyone out there be able to let me know how to do this? On the iPad there is just one login for everyone (although different google accounts?). On the PC we each have our own login, although DS has set himself up as an Administrator as well as me. Is there a way of removing DS's Administrator status if needed?

Many thanks, in advance.