For your goal of running 9’s in the quarter, you car is no longer a street car, it’s a race car you can drive on the street, big difference. Unless you plan on driving a lot at highway speed then build for the track.
The TH400 has already been proven in a fox chassis with cars running faster than 9’s. Heck the TH400 has been run in a variety of chassis behind different engines making 1200+ hp. Lots of support for this trans, tons of aftermarket parts and it’s easy to freshen up when needed.
If you are happy running 9’s and don’t plan to go faster, then you should look at the 4R70W. Skip the AOD, even with 4R internals the pump still sucks plus you would have to run a manual valve body, even then you are at the mercy of the valve body short comings.
The 4R can easily be built to hold 800+hp, there’s a couple guys who can build to 1000hp but this requires welding planetary gears etc. And yes , you will need an aftermarket controller or go manual valve body. Don’t fear the electronics, they are robust for this application. Heck you can lock the converter is 2nd - OD , this allows for extra rpm at the top end. I run a 4:10 rear gear. I can run at 70mph in OD with the converter locked and keep rpm around 2500rpm, fine for highway.
For race, TH400 is the only way to go. For street, a well built 4R fits the bill. FYI a good triple clutch 4R converter ain’t cheap so factor that into you decision.