Most people who post say their children loved the clubs. I'm in the minority here.
Yes, our 7 year-old DD was bored. (We first cruised 3 years ago.) She was cooperative about attending at night, whenever DH and I went to the nightclub. However she preferred being with us during the day.
She was 9 when we sailed last summer, and had sign-out privileges. It worked much better. There were only one or two activities that appealed to her, and she was able to come and go as she pleased. (She had to go back to our stateroom when she left, or stay with us. We had walkie-talkies.)