Since all octopuses change their shape and colors, it would be helpful to know the size (which doesn't usually change). Possibly abdopus acleatus based on the coloration and shape. Could you post more pics that include other color changes (if it does change) and write what size it is?
I vote with 99% comfort that it is O. hummelincki. Abdopus is not Caribbean. O. briareus is Caribbean but quite different looking. Have a look at ET's journal. So glad to see these guys back in the Keys! Great animal. If you watch closely over an extended period of time, you will see a false eyespot (very often not visible) below each eye. When fully displayed it will be a blue ring around a yellow circle with a blue center. Not all the colors are always visible when it is displayed but they are there. Sometimes it looks like a circular pucker with dim colors, when they are displayed, they can be quite colorful. Et almost never shows his eyespots and have me wondering about his species for over a week.
In my limited experience (along with some reading) they can vary in size from close to dwarf (Maya was close to large dwarf size and I think ET may be as well) to having a mantle (but not arm length) of O. briareus (max arm length I remember was roughly 8 inches). Here is the O hummelincki thread in Cephalopod Species (by family) that has a bit of technical info and a nice video.