Oh dear god it worked, it worked!
Acraeus, I could pay you a beer right now.
I just unbanned myself from 002 using nothing but my own 3DS! This is incredible. And I suck at writing tutorials of any kind, so please don't count on me when it comes to that!
But basically
1. Inject an old NAND backup from when you were still installing a9lh (I did one before)
2. Use Decrypt9 to extract movable.sed from it
3. Use Decrypt 9 to extract movable.sed and LocalFriendCodeSeed_B from your current NAND that is banned
4. Use HxD (hex editor) to compare your old movable.sed with your LocalFriendCodeSeed_B, see how offsets 00000000/08 through 00000110/07 is the SAME!
5. Open up your NEW movable.sed with HxD and copy offsets 00000000/08 through 00000110/07
6. Open up LocalFriendCodeSeed_B with HxD and CTRL+A and then paste what you just copied
7. Save, inject to sysnand
This is how I did it, don't blame me if something goes wrong because I'm even worse at giving instructions than following them.
EDIT: Ignore strikethrough text, that is no needed and was just a part of me finding out HOW to do it, you don't need to do that.