Island cruises have a good video have a look here at this link
It will give you a good idea what to expect. Given the time of the year it seems reasonable there will be other kids on board as the school holidays are still in full swing. You will get a talk a few days before you leave the ship on how to pack as you will need a hand case for leaving the ship on your last day as your main luggage will be taken away late on the last night, but this will all be explained by a member of the crew and if your to happy ask them any questions and enjoy your cruise.
I'm a single parent and always travel with my son (15 now). 4 cruises over the past 2 years - successful. Active entertainment teams on board, with activities geared up for teens so they can meet each other. It's great if they do find a pal, but doesn't always happen. Cruising is definitely an easy way to travel for us singles, as there's no embarrassment; your son is safe to explore the ship whilst you relax and have fun.
Hi, we have a 11 year old boy , but he would probably be too young for your son. But you never know???