Welcome Oleg! Your initial question about Florida may get more answers if you posted in the
Florida forum.
To answer your question about other warm water destinations in the US:
I haven't been diving in California, but it's my understanding that all of California is cold water diving. Even in San Diego which is in the south, the water is between 50F (10C) and 70F (21.1C). In addition, I believe it's also more advanced diving in general compared to many warm water destinations.
Hawaii might be an option for you, however, it gets expensive.
I've heard some wonderful things about the Flower Garden Banks in Texas which would have warm water in the mid-80s I believe. (That's in F. In C, ithat's around 29.4 C.) And I believe their summer season is still in effect in late October. Texas on is my list of places to dive so I haven't been there, but I've heard that many of the dive sites are advanced & that these are all day boat dives or liveaboard dives.
North Carolina has some great diving, but it's not really warm in late October. Usually between 68F (20C) & 76F (24.4C). I believe many of the dives are also more advanced dives.
I believe Puerto Rico & the US Virgin Islands are not an option due to hurricane devastation. I'm not familiar with Georgia nor South Carolina diving, but these may be problematic due to the hurricane as well. Not sure. (I assume that the US territories in the South Pacific are not under consideration for you when you say the US.)
Those are all the US warm water dive destinations I'm aware of. You can take a look around all the forums & dive clubs underneath the
US forum for more ideas, or post a new thread in
General Travel and Vacation Discussions with a subject line to the effect of: Warm Water Diving in the US - Late October?
Hope you find a great destination. Happy diving!