Sounds good, you should be able to install the MSET exploit using a DS flashcard (I -think- -9 is high enough for that), or simply use go.gateway-3ds.com to run the GW Launcher and create emunand partition.
From there, you can get rxTools and run it via browser, or via the MSET exploit which can be installed with a DS flashcard or the browser exploit. Once you have rxTools running, you can inject FBI into Health and Safety app on sysnand with rxTools, start up in rxtools devmode/pasta mode, install sysupdater latest version with FBI, then update to 9.2.0-20E, run browserhax to install menuhax for autoboot rxTools, etc.
This is a very rough guide but basically I believe it should work. We can go more in-depth later, there are also guides that go much more in-depth such as
this one
Lowest browser version supported by Ninjhax 1.1 was -7 so I assume -9 should be fine for other exploits, but then again, they aren't the same exploits.