Well that’s a bummer but I think the SBA4 should work for the braceYou're going to be too short for an SBR if you live in Md. You will have to make up a 3.5" shortfall to make the 29" minimum overall length. There are solutions for that...
That said, if you live in Md, you can keep it as a pistol and go back to using a brace. Md. is OK with braced pistols, for now.
ETA: Understand that, if you do take you AR9 pistol out of Md, you will have to remove the brace. It will then become an unregistered(with ATF) SBR with the brace on.