This is a pretty good site. It shows planned cruises and also shows "cancelled" next to some.
I'm sure this data is legging reality but it is better than many sites including the cruise lines which appear to be selling their old itineraries and will substitute the stops (some announced) when the time comes.
Carnival Vista is not currently cancelled for 12 October. Not sure what, if anything, to read into that as other Carnival boats before/after are cancelled. Maybe whole cruise cancelled out of San Juan.