Your best option is to grab a DS flashcart (R4 are very cheap nowadays) to install the MSET exploit and that's basically all you need + it can always be handy to have one
My advice is:
Buy a sky3ds (whatever version)
Put cubic ninja rom on it
Dump otp with cubic ninja
Update to 9.2 with a rom containing the 9.2 on your sky.
Launch the homebrew launcher with cubic ninja or any other game via your sky.
Install A9LH with your previously dumped OTP.
Update to latest...
You don't create an emunand, you update to 9.2 first via rxTools MSET, it's all here:
https://github.com/Plailect/Guide/wiki/9.2.0-Update-(rxTools-MSET)
Don't worry, if it's the wrong otp file the installer will detect it and won't continue
When you use SafeA9LH it does some security checks before proceeding for people in your case