IGNORANCE AHOY!!!!!!!
Honestly, I have been an EA guy for years, and this year I gave both titles a shot, and here is my honest review/opinion of each, coming from a long-time hockey and video game fan.
NHL 09: I'm not going to lie, this game is amazing. The graphics are fantastic, and the gameplay is very smooth. There are a few minor problems that over time have really gotten to me. First of all, no matter what difficulty you play on, the opposing goalie always plays amazing, while your goalie plays like he has a blindfold on. In Be-A-Pro, your teammates are absolutely RETARDED, and refuse to do anything but give you the puck. The Dynasty mode lacks any sort of real depth. That doesn't mean its bad, but it lacks any sort of fantastic outstanding feature. However, if you are in it for the online play, you will either love it or hate it. There are lots of people who cheat/do cheap goals constantly, which you will see VERY quickly. However, the EASHL is absolutely amazing, but once again, full of cheaters/cheap goal players(EASHL is basically playing on a team as your created guy, with other people playing as their created player). It is alot of fun, but can also get frustrating very easily.
Pros: Good gameplay, skill stick is alot of fun and gives you lots of creativity with the puck, EASHL is a genius idea, Be-A-Pro is very fun, fantastic graphics
Cons: Cheap/cheese goals online, and EVERYONE does them, game gets sort of repetitive, stupid teammates, lots of goals are similar(high glove side, one timers and dekes).
NHL 2K9: Once again, going to be very honest, I was skeptical about this game after playing the demo. However, at the recommendation of a friend, I rented it and boy was I glad. It took a little while to get the controls down good, but they felt very comfortable, and I never felt like I was fumbling to try and find the right button to do something. Graphics aren't terrible, but they definitly are miles behind NHL 09. Gameplay is much more arcade-y, but that isn't a bad thing. It is definitly a whole bunch of fun. If you mess around with the sliders, you can get any sort of game that you like. It can be a run-and-gun 10-8 goal fest, or you can have it as a very realistic, medium pace battle finishing at 3-2 or 3-1. The AI is very smart(for both teams), and unlike NHL 09, there are shots that go in that aren't the same play over and over again. There is no manual shot aim, but I never had a problem with shooting into the goalie with a wide open net or anything like that, and not every goal is a one-timer or high glove side. You can really feel the difference between your top line and your 4th line, which is a nice touch, and really helps play into strategy of trying to match your 1st line against their 4th line, and avoiding having the same thing done to you.
Pros: Very fun, easy to pick up and play, good in-depth franchise mode, no game ever feels the same(occasionally you will play a game and score 10 goals, then the next game, play a worse team, but because of their particular defensive strategy, you have a hard time beating them), balanced gameplay(never feels like the computer "cheats" or has amazing "comeback" abilities).
Cons: Graphics aren't awful, but they are not nearly as good as NHL 09, occasionally over-realistic gameplay gets annoying(players colliding into each other while just skating, checking teammates, pucks/players hitting the referee)
Judge for yourself, I would say at least play both before you buy one or the other. If you have any questions about either game, feel free to PM me or post them here