Make sure you get the right pollinator apple for the variety of apple you want to grow. Most apples aren't self pollenating, and need a different apple or two to ensure fruit development. For example, if you wanted to grow Anna you would need to also plant a different apple tree to ensure the cross pollination needed for the Anna flowers to become fruits. Make sure your apple trees are planted within 50 feet of each other. Yes, some self-pollenating apples are out there, but they too benefit from another pollinator apple. There are lists out there for companions, so no matter what apple you pick for your main, you will find a list of other apples that go well with it.

Consider chill units. In 8b you are going to have fewer chill hours than in a colder zone. Almost all apples need some chill units. Look for ones that need less units. Chill units are the hours during the winter when the temps are between 32-45 degrees. Be aware that chill units is not your growing zone or hardiness- those indicate the minimum temps your area can get to.

Also consider your tree size. Some come in a more dwarf size, some of them can get pretty big.

The best resource for selecting a tree fruit that will do well in your location is your county extension service. Their entire purpose is to help home gardeners select and grow the plants best suited to their specific location.

https://extension.uga.edu/topic-areas/fruit-vegetable-ornamentals-production/apples.html

If you want only a single apple tree, you can pick a flowering crabapple as a pollination partner. As long as the bloom times coincide, crabs are an excellent and very ornamental pollination source without the same care - or space - required for another apple. This is a trick that commercial orchardists use as well.

I'm in the Dallas area which I think is the border of 8a and 8b. I have a 3 year old Golden Delicious that's growing like a weed! No fruit yet but I suspect I'll have some on the tree next year.

USDA zone designations really have no bearing on what apples may thrive in your climate. It is far more likely to be determined by necessary winter chill units and sufficient summer heat and timing thereof to ripen the fruit successfully and only your local fruit growing organizations/extension service can provide that info for you.