What is on Google Maps as the "Kayak Boat Ramp" is the official spot for diving now and is a perfectly good launch point for kayaks. Not a whole lot to see unfortunately but if you're wanting to practice getting in/out of the kayaks it is the right place to do it.
What is on Google Maps as the "Devil's Fork Road Boat Ramp" is the old diving spot and has a few more interesting things to see but is no longer protected and has a pretty steep ramp to get in/out of and diving is technically not allowed there anymore.
The Wall is much more interesting of a place to dive, but it's a 2.5mile paddle each way and you're going across open water with all of the Muppets driving boats, have to contend with wakes, etc. Despite being a much more interesting place to dive, if you're trying to practice diving from your kayaks, it's a long ass way out if something goes wrong.
I would launch at the Kayak Boat Ramp as the Park has asked us to, you can always make the short paddle over to the old dive area just around the point if you get bored, and use that area as your practice spot. One of the nicer things with the current dive area is it doesn't drop off terribly quickly and is largely protected from wakes so if you are struggling to get in the boat you can always get to an area you can stand fairly easily and once you're comfortable enough to make the 5 mile round trip paddle to the wall it will give you some more interesting things to see