A9LH = arm9loaderhax, which is the best method of booting directly into CFW instead of using an exploit each time to do it. You can still access the eShop, and perform system updates. It allows for easy backup/restore of the firmware, as well.
The process to install A9LH is here:
https://github.com/Plailect/Guide/wiki
The minimum time to complete it is just over 2 hours. On average, it takes about 3 - 4, if you don't screw up. The majority of the work that has to be done is to get a 256 byte file (OTP.bin). LOL.