Konichiwa!
The Hiroshima port currently lists Itsukaichi dock for this cruise, as it does for every docking of the Millennium. Here is a link to the current 2024 port schedule. Look for the date and ship and plug that row into google translate.
Here's the output:
33 Celebrity Millennium 2024/7/19 Fri 13:00 2024/7/19 Fri 22:00
Itsukaichi-11m, -12m quay
My TOTAL GUESS is that there is a shuttle bus between the ship and Itsukaichi Station.
I'm on this itinerary leaving next week. I'll try and report back.