Hey, ShadowNAND and the A9LH v2 with a mini-CFW are both still a thing.So it would start without an SD card even before the update? You definitely didn't have A9LH on there then, unless you used the alternative payload.
But it does sound like the OP didn't install A9LH properly. If they followed the guide, it only brings you up to V2 without the mini-CFW. So it should have just turned off when you booted the system without an SD card.