The 9MM is a great choice and there are a ton of fine choices out there. Your best bet would be to handle as many as you can in your price range and then try to rent and shoot the ones that appeal to you.
Now having said that I don't know your experience in firing handguns. If not much I would suggest first trying to get some professional training that many local ranges offer at affordable prices that can help you with tips like stance, grip, and trigger control and demonstarting the difference between the various trigger action types such as DA/SA hammer fired and striker fired such as a Glock and safety option. Once you knwo those basics you will have a better idea on selecting a pistol that fits ou well and works well for you.
While there are a lot of fine pistols in your pistol price range I would suggest if possible to also look at some more expensive pistols if your budget allows it as over the long term for most shooters the actual investment in the pistol will be a small part of shooting costs and a couple etxra hundered dollars over a period of years is insignificant if that means getting the pistol you really want and shoot the best rather than what is simply good enough.
I have tried practically every widely available pistol out there and my very top choice are SIGs such as the incredible SIG P226 though it is a bit big and heavy for carry. Closer to your price range I HIGHLY recommend the Walther PPQ or the SIG SP2022 that is well within your budget. The Glock 19 is also a very fine choice and one of the most awesome all around pistols ever with tons of accessories available for it. I own all these and have a personal preference for pistols with no external safety.
Good luck in your quest!