In terms of the upcoming 2024 season, it's a case of whether your cruise line (not you) booked the itinerary before the referendum vote (ie Nov 8, 2022). So if Royal Caribbean, for instance, had the paperwork for your cruise with a Bar Harbor stop "on the books" before that November 2022 vote, that ship's Bar Harbor stop would be grandfathered in. If your cruise line (not you) booked the itinerary after Nov. 8, 2022, theoretically, you would be unable to stop there.
And yes, any appeal by the plaintiffs would probably keep the cruise season open while it's worked out in the courts.
Some interesting insights on Sea Trade Cruise News including a quote from a Holland America rep saying all their 2024 cruises will go on as they were locked down before the town vote.