Preparation
Wash off the chalk and biological growth, and let it dry properly. Repair the stucco first, not after. Caulk every joint at trim, windows and penetrations. Prime bare and repaired areas. Painting over a dirty or damp wall is why the second coat peels.
Product
On masonry, use a quality acrylic elastomeric or a high-grade acrylic. Choose it for UV resistance rather than price per gallon. Stucco also needs to breathe. A film that traps moisture in a block wall blisters, which is a common and expensive mistake.
How long exterior painting should last here
Well-prepared work on masonry runs the better part of a decade. Badly prepared work chalks in three years, and the difference is almost never the tin. Wash off the chalk. Repair the stucco first. Caulk every joint, then prime bare areas. That is most of the labour and all of the lifespan. Where the wall still lets water in, painting is premature, and the Florida Building Code has something to say about the fix.
Timing
Avoid the wettest part of summer. Avoid painting a wall in direct afternoon sun, which flashes the film before it levels. Work early in the day, on the shaded elevation. That is how it gets done properly here.