i would assume any of the family friendly cruise lines would offer such sitting sercives. the cruises geared toward couples and romantic cruises might not. check with the websites of the various cruise companies or your travel agent.

Next question are you ready for a 9 month old to be left with a strange sitter you are not familiar with on a cruise ship? if you are i would still ask about the certification of the sitter. you might not want to leave your baby with someone who got the job only because they are the 15 yr old kid of the ship captain