Does that not require both systems to be <9.2?
If you have a 9.9 system, just start the sysTransfer like normal on it. The 9.0 system will require NTR to spoof the FW version.
I thought encryption changed after 9.6?
This will probably not work for you.
Your main problem is the fact that one system is on 9.9 and the other will only be on 9.2 (or 9.5 for emunand) and the encryption (and transfer protocols) changed in 9.6.
Afaik the original limitations for using the firmware spoof still apply, meaning transfers are limited to the following sets of source/destination firmwares:
Source : 3.0 <---> Target : 3.0
Source : 4.0-4.5 <---> Target : 4.0-4.5
Source : 5.0-6.3 <---> Target : 5.0-6.3
Source : 7.0-8.1 <---> Target : 7.0-8.1
Source : 9.0-9.5 <---> Target : 9.0-9.5
Source : 9.6-9.9 <---> Target : 9.6-9.9
That's what I thought
I was thinking that I could use a exploitable 2DS as a surrogate but you can't transfer from new to old :/
Am I screwed until N3DS 9.9 emunand is possible?
Seems like it. You can always xfer your purchases and re-download, but the saves would be lost which is what you're after.
How would I transfer purchases?
I'm not sure about system transfer, it would probably work but you would have to wipe system after and then re-link your NNID. You could also just call Nintendo and tell them you want to transfer the NNID via serial number and they will do so behind the scenes for you.
If I call up Nintendo and tell them that my 9.9 N3DS is broken, can they transfer my purchases to my 9.0 N3DS? And if so, will my games still be usable on my 'broken' 9.9 N3DS?