I'd say see if there's a range nearby that has a good rental selection. That way you get to hold and shoot a bunch of different pistols so you can have a physical notion of how certain guns feel over others. Personally, I love the feel of a Sig P226 in my hand, but I don't shoot it anywhere near as well as my CZ-75B.
If you're really looking for something different and decide to drop the 9mm requirement, revolvers would be an excellent way to go. There's a lot to choose from there as well, but S&W and Ruger both have affordable quality offerings.