Yeah when I bought it, the damn thing was already in 10.something. Shame, I got this for $10 and wanted to see how to do it.You are out of luck, to use CFW or Gateway you need to be in 9.2 or below...
The only real option you have to play 3DS roms is called Sky3ds, is a flashcart.
To play older games you can use Themehax, is a free hax but you need another entrypoint to get it running (You could use a Cubic Ninja rom in the Sky3ds to set up Ninjhax and then install Themehax).
So in a sense I will need to spend money on a flashcart? And I saw that if I bricked I would need an Arduino. I got a Fubarino I used from my college course. Would that work as well seeing as both are programmable the same way? I learned that Arduino has a better interface since it tells you what line of coding was wrong. What I used for my course didn't.