Hi
I was last at CM last year with 5 kids ranging from 8 - 15.
I can only comment on Siesta's kids club which was great, all tour operators have their own one.
Even if the older kids cant get into the kids clubs there's still plenty to do (12 was the oldest with Siesta). Every day there's kid's entertainment at the panorama pool from about 12 onwards, that's if you can drag them out of the pool!
Apart from that there's mini golf, tennis, internet or just having a wander around the camp site is great.
It can get rowdy with the older kids, mine got into a few scrapes 2 years ago but you'll find the camp site staff are really quick at putting a stop to it.
Now all kids have to carry their camping pass which has their DOB on it which stops underage kids buying drink and fags and getting into the underground disco. (Nothing will stop the older kids from doing it for them tho)
The kids will love it there, just keep an eye on them and they'll be fine.
The only "problem" area I've ever noticed is around the pool table at the panorama pool, all the kids seem to hang around there hanging out the windows and at the top of the underground disco late at night when its on.
If the kids get fed up on site with the entertainment which I doubt they will there's a bowling alley on route to the beach. It's only open at night and it's really cheap for a game.
If you want any pics or more info let me know. I've only been 6 times with kids of all ages. (Not all mine either!)