I bought my R9 (my third handgun) in December, and here's what I've learned:
1) Use quality ammo ONLY. After a bad experience with cheap ammo, I now only shoot Speer Gold Dot Hollow Points (115 grain). Bad ammo will give you lots of problems, so just avoid the temptation to save money.
2) Check your grip screws after every trip to the range. If the right grip works loose, the trigger spring can come unseated. Use a new 1/16" allen key to tighten the grip screws, and blue Loc-Tite if they keep working loose.
3) Change your recoil spring after every 100 rounds (the factory interval). When I changed mine, the replacement was about 1/8" longer than the worn out spring.
The R9 can be a punishing gun to shoot. I would STRONGLY recommend the purchase of another gun to get proficient with shooting a handgun (can't go wrong with a 9mm Glock, for example). I put about 4x or 5x the ammo through my Glock 36 (.45 cal) than I do through my R9. I now shoot my R9 just enough to stay proficient.
Congratulations on your new purchase, shoot safe and welcome to the board!