Attic Insulation in hot and humid climate
Any good paint on ceilings eliminates the need for vapor barrier. As far as which way to face a barrier if your climate is hot most of the time and you have air conditioning then face toward living area (ceiling) since inside air is cooler than attic. I.e. a cold glass of tea sweats on outside of glass. But my field experience says vapor barrier towards attic is a moot issue. Since you (should) have at least 8 inches attic insulation and that R value will buffer any temp exchange before it gets to ceiling material. Even on the walls I've never seen any mildew or evidence of excessive sweating due to lack of vapor barrier. I have seen such with rain leaks. Maybe in much colder climates walls would need a barrier.