I'm actually saddened by the way people are being unhelpful to you (from my point of view at the very least). The EASIEST way to play online is to just do it with either an installed game or an original cartridge. Playing roms with the Sky is literally the only thing that can get you banned from online. Installing a CFW is way more convenient and it cost nothing. If you really don't want to deal with doing it yourself for whatever reason, it probably still would be cheaper to just pay someone to do it for you.
And to the guy who post the a9lh guide, maybe you had good intentions, but you just send someone who knows nothing about the 3ds and wants to spend as little time in hacking it as possible to the HARDEST hacking process there is. Like really guys, 100% boot is nice and all, but to most people it isn't worth doing all that extra work and half breaking their 3ds. That guide still can be useful to you OP, but just leave it at the CFW part and enjoy your console, if you find the the 90% boot rate to be unbearable for you, you can always continue the guide latter.