There's no such thing as a stable/unstable a9lh [well except in terms with how the dev would classify the a9lh payload]. It's either installed or the system is bricked. All the files on the sdcard are re-creatable except for otp.bin - which is only need to reinstall a9lh from stock firmware.
If you are starting from a fresh sdcard, setup your arm9loaderhax.bin [as luma3ds] and your /luma/payloads then aeskeys.bin in files9 folder and load up hourglass9 and make a nand backup - I'll create a nand.bin and backup a few other files.
@NoNAND was it just a simple sdcard removed without unmounting corruption that was fixed with a simple chkdsk [scan and fix]?