You have to rent your tux before your cruise - you cannot book it on board.
This is the info I got from HAL's website under PLANNING & ADVICE
Clothing & Dress Code
Formalwear for ladies and gentlemen can be pre-ordered for your use during your cruise by calling Cruiseline Formalwear at 800-551-5091 or make your reservations online. Your formalwear will be in your stateroom when you board. Cruiseline Formalwear Packages
I believe that any alterations that need to be done can be made on board by the tailor.
I rented a tux for a Princess cruise and it was not there whwn we checked in. The company told Princess I had cancelled, which was not true. Kudos to Princess for putting a tux together for me and I'm not easy to fit!!!
My husband rented a tux for our Hawaii cruise. We preordered and everything was in the cabin upon arrival. He rented the shoes too but forget to bring his black socks. There were none to be found on board. I had a pair which he used but were very stretched out.