Hi A.,...
I have not been on a cruise,.. but have traveled with my sons quite a bit.
For the most part,. I have often over-packed for the baby.
Bring a box of his favorite infant cereal. and only a few baby jars of food you know you baby will eat. This is not the time to test new things.
You mention bringing a mini processor.. but do you really want to have your baby sit thru your meal - just to go back to the cabin and feed him... I don't know if you meant you bring the mini-processor to the table in the dining room.
my advice is to keep it basic,. to the things he likes and I'm sure there will be plenty of things for him. Rice,. bread,. fruit,. oatmeal,. like the other posters already mentioned from what's available on the cruise. It's only for a short while - he won't get bored of it.
I would also suggest you bring your own baby spoons and some small plastic bowls.