If you're serious about having firearms for home defense, don't just stop at the firearms. Ensure you have a well thought out defensive plan, as well as other gear - body armor is very cheap, even buy surplus if you have to, and store it near/with your firearms. Keep at least one good flashlight with your kit (most encounters in home defense will be in low light), and train how to use it with your weapons. Also keep a backup cell phone with this gear, even a phone not on a plan will connect to 911, so throw an old cell phone or 2 that are charged into that kit bag as backup emergency comms. Lastly, but most importantly, have a first aid kit designed for gunshot and edged weapon trauma, and take some training on how to employ it - 2 tourniquets, quick clot/bandages, suture kit, relief valve/needle, gloves, scissors, etc etc. Should you be involved in a shooting even in your own home or on your property, L/E will often want to secure it before letting EMS in frequently, and if you or any friendlies are wounded, it could be down to you to treat wounds until they have access, and some simple gear can make a huge difference in life expectancy.
Consider how you're going to store your firearms in your home, if you are going to leave them loaded for self defense, I highly recommend getting a fast-action safe to store them in, something with either biometric or electronic combination locks. This is for not just safety reasons, but liability ones as well. Lots of cheap, fast, solid options here, you can mount small units to your bedframe for handguns, or bolt them pretty much anywhere, and standing/rifle vaults are easy to find as well.
Sounds like you want a double stack 9mm, so I'd go with your instinct and gut and move in that direction. There is a phone book of options in that department, just try a bunch out to see what fits your hand and has the ergonomics and features you want. The Legion you mentioned or any of that line is something that will last you a long time, and fit the bill, but will be heavier for future carry due to the metal frame. I'm biased having worked for Sig Sauer for a long time, and there are other good options out there as well.
Regarding training, since you're just starting out, get yourself some good fundamental training from a solid instructor, there are lots of options in your area, just do some background research into them so you don't get some yahoo. There are many solid schools out there, when I first instructed at mine (Sig Sauer Academy), there were really only a dozen or two circa the early 2000s, now there are hundreds of professional instructors and schools. Again, you should focus on learning the fundamentals of safe and accurate pistol shooting (and rifle if you're getting one for hunting), before getting to worried about getting spun up on more advanced handgun/CQB skills.