Yes, youth perks do include internet.
Just follow the steps to purchase internet, and the info you enter will bring up your discount and you'll "buy" a day of internet for $0.
I wouldn't want kids sitting at the bar for extended periods, especially if the bar is otherwise full. But kids coming up and ordering a drink is no big deal.
Like I said, I'm sure it was a one off, but they forgot to prep what my wife ordered the night before on three nights, and one night even said "sorry, there's nothing we can make gluten free for you tonight" on one night, which of course was BS.
I've only had one cruise on a ship with a CK and we weren't impressed. They did a terrible job with food allergies, too. I'm sure that was a one off, but we've never tried to book an Oasis ship since.