Apples and oranges. DACP/FP is a great combination. No reason not to use AIO before SG.
#9 after DACP is a different situation. #9 will remove swirls, but will also leave oils and fillers to hide swirls that might not have been removed. AIO is a robust cleaner which will remove the makeup, and the hidden swirls will reappear. If you don't need to hide anything, it's OK. Follow with AIO/SG. But I don't know how well SG will work without AIO. AIO prepares the paint so it will bond well with the SG.
If you need to maintain the fillers to hide swirls, try Poorboy's EX. I think that can provide you with a good-looking long-lasting "sealant" without removing the fillers. Einszett Glanz Wax might also work, worth a try.