u wot m8???Prove it post a video of you doing exactly what i had just said to your 3ds.
If you really think it wont work then you will have no problem doing so
GM9 doesnt magically know how to remove the b9s from your firm partition.
Restore nand means it flashes the chosen nand image into your 3ds nand.
If the image has hax, the resulting flashed nand will have hax.
Btw, the burden of proof is on who made the claim, which in this case, YOU.
Post a video of what YOU claim it to be or sit in a corner and educate yourself.