How Do I Block YouTube On My iPad?
From your home screen, open the Settings app and tap on General. Scroll down to Restrictions and tap it. From there, tap on Enable Restrictions. You will be prompted to create and set a passcode. Enter it twice and then switch the On/Off slider next to YouTube to the off position. This screen also lets you block other apps, disable in-app purchases, and restrict other content.
Note: if you disable YouTube, the app will complete disappear from your iPad until you enable it again via Restrictions in the Settings app.