OK I figured out how to lock the apps. Still looking to lock the internet settings.
TV: Samsung UN65JU6700FXZA connected wirelessly to Netgear R6250 router with DD-WRT firmware on the 5Ghz channel.
I need to passcode lock the smart hub apps and would like to be able to passcode lock the TVs internet settings.
Problem is the kid wants to stay up late on his PS4 upstairs in his room. PS4 only connects to 2.4Ghz radio signal so I have that channel set to turn off at a decent hour. The 5Ghz channel (which is what the TV "was" connected to)was set to turn off later so my phone would have wifi. After the 2.4 shuts his PS4 down he comes downstairs and wants to stay up late watching you tube videos with the smart hub app.
So I set the 5Ghz channel to shut off an hour before the 2.4 so he wouldn't keep us up with these silly gaming videos. Now he's learned how to change the TV to the 2.4 Ghz channel for an extra hour of videos!!!
We would be just as well off to block the You tube app all together. Is this possible on this model? Would also like to passcode lock the TVs internet settings from being changed also.
Any suggestions on how to do this? If the Apps can't be locked on the TV is there possibly a way to block them in the router?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic