I have no knowledge of the iOS system, asking this on behalf.

The need is to control/limit access to Youtube while allowing access to other sites on an iPad.

Is there an app that will do this that can not be easily subverted?

Ideally something that would have a timer function to allow access for a set period of time.

I am imagining a scenario where the adult unlocks access via a password and is able to set it for say 10 minutes after which access is locked again.

Thanks.