It goes back further.
“The first reference to a cracker in Florida appears in 1790, when the Spanish governor of East Florida wrote that the crackers in Florida were wild, nomadic and would not heed government authority.”
Gradually it became a turn applied to Florida cow hunters who cracked whips when rounding up the pretty much wild free roaming cattle in Florida.
Coincidentally, the American Rifleman, April 22, has an article “Cavalry Arms of the American Revolution with a slightly earlier reference ( but not Florida, rather the Colonial South):
“With rifles and sabres, these men were more on the order of what Europeans would term dragoons.
A British officer aptly described the mounted Patriot militia in the South, ‘… The crackers and militia in those parts of America are all mounted on horse-back … . When they chuse to fight, they dismount, and fasten their horses to the fences and rails; but if not very confident in the superiority of their numbers, they remain on horseback, give their fire, and retreat, which renders it useless to attack them without cavalry … . ‘ “