Mine is in a container in a heated greenhouse. A container is probably good for you if you have any chance of frost in the winter. I see your zone9 low temp is ~25-30F, so you should move it indoors if there is a frost advisory.
I use osmocote plus 25-5-15 (the pink bag, most common type) to fertilize, and a free draining soil mix. You should change the container soil every year, and move it to a bigger pot then if the roots are circling around.
Also, you may have Citrus Greening disease on your area, aka Huanglongbing. I'm not sure how widespread it is in Florida.