My daughter was 8 on our first cruise and never asked for check out privileges. It is just the two of us travelling together so there's not really any reason for her to have it. She will be 9 on our next cruise and I'm sure if she wanted check out privileges I would allow her if needed with a lot of restrictions and requirements. We go on vacations to spend time together and enjoy going to the shows, movies, excursions, meals, etc. together. She does like to go to the kids area so I try to schedule some adult activities for myself so she has the balance of that too.
There were some kids on our last cruise that were very rude in the elevators, jumping in front of people that had been waiting for the elevators, running all over, running into people, etc. I agree with the pools too. There were some very rude kids whose parents clearly weren't watching them. They were "controlling" the ladders and wouldn't let kids out of the pool, they were pushing my daughter and saying mean things to her. She didn't want to stay in the pool long. I agree that the pools were quite disappointing. I would certainly tell a first timer not to talk up the pools too much to their kids. The free ice cream on the ship and at
Castaway Cay is pretty amazing though!