We have been on 4 cruises with this company and they have always allowed us on board earlier than stated but you cannot get into your room until later in the day but lunch is usually being served and you can buy drinks at the bar.
I have been on 7 cruises with RCI, check in started earlier than what the ticket said on most of them. If your aunt is disabled you should get priority boarding, ask one of the check-in staff. Good Luck and enjoy your cruise.
Don't tell anyone else but RCI normally start loading at about 1100am in Barcelona. We always arrive at this time & walk straight on in BCN, well before most of the package flights have even landed. As stated below you won't get into your cabin till 1pm so take shorts & T shirts etc to chill out on deck whilst the others queue on the dockside. The time on your ticket has no relevance.......Regards Wilba.
We travelled on IOS end of aug last year and arrived in Southampton around 10am. We were on board the ship by 10.40. Did not get access to our cabin until around 2pm, but it was great as we had time to do a bit of exploring. Enjoy your trip.
We went on the independence of the seas in aug 2008 and our check in was 2.00pm but we were in the que for ten and on the ship by eleven. hope this helps.