Artmc, I'm also booked on an October cruise (Oct 9 Rome to Venice) and, like you, I'm concerned about the lack of information regarding AZ's policies, especially with the Greek sailings beginning just one month from now.
While your vaccine question is not an issue with me (and it looks like it was well answered for you above), I did call Azamara Circle the other day with a series of Covid-related policy questions, including a couple of "what if" scenarios regarding testing positive during or at the end of the cruise and what help might be provided with arrangements for isolation, etc. The answer to each was "We don't know yet. They're working on it.". Other cruise lines (I think Princess's policy was posted here a few weeks ago) have these details posted on their website.
I realize the complexity of their situation where things seem to change by the minute, but there should be some baseline policy by now, subject to change.
Maybe others here have been able to get some answers?