A lot is going to depend on his personality. Some kids love the clubs and want to spend their entire cruise in them, including skipping dinners, skipping shows, etc. Other kids are overwhelmed by the relative chaos and would rather be off doing things with their families.
I'm am very much on team "family vacations are for family time" and we use the clubs sparingly, maybe an hour or two per day and only on sea days. Most of our time on the ship is spent doing activities (get familiar with the Navigator app quickly) and on the pool deck. Our kids love the dining rooms and the main theater shows, and their fondest memories of cruises are the interactions with the dining room service team.
For reference, we've cruised 5 times since the COVID reopening with kids the following ages:
7, 4, and 1 (double-dip)
7, 4, and 2 (double-dip)
7, 4, and 2 (Alaska)
8, 5, and 3 (Bermuda out of New York)
9, 6, and 4 (Mediterranean)
Two of those were double-dips, and our favorite thing to do was just to rent a few floats for the family (they have a discounted rate if you rent for both days) and plop ourselves on the edge of the water.
My general advise for Walt Disney World vacations applies to cruises too... make sure everyone gets enough sleep, which probably means making sacrifices. For us, we do really well beating the crowds in the early morning so we tend to skip late-night activities and go to bed early. Other people might want to stay up later for the shows which means they're going to need to sleep in or take naps. If you let anyone get exhausted, you're all going to end up crabby and fighting no matter how much you tell yourself you won't.