I am kinda new to rims (and cars for that matter) and I am looking into getting some. I really like the Enkei ones. I have a few questions.

On some rims, they are 17x9 or so. Obviously the 17 means the diameter of the rim, but I don't really know what the 9 means. I am guessing it means the height (if it was laying flat). Is that right?

What would fit my car? I have an 04 Lancer ES. And what are some good sites to order rims off of. Thanks.