I understand this is the general advice in the UK, and you shouldn't do anything you are uncomfortable with. However, in the US they do not give the same advice. And by the time your baby is old enough to go on a cruise, they are also old enough to chew on the remote control, kiss the dog, lick your phone, etc. so clean but not sterilized water would honestly be the least of my concerns!!
I did cruise with both of my kids before they were a year old. We ran water through the coffee maker and used it to warm up bottles. I took a bottle brush, small container of dish soap, and a portable drying rack (https://www.amazon.com/OXO-Tot-Drying-Bristled-Cleaner/dp/B07YP59DQ7) all of which I highly recommend, along with disposable bibs and a lot of extra baby wipes! 🙂