I'm not familiar with the 09. But when I was shopping for a used Escape, the one of the common problems I saw was rust in the fuel filler cavity (inside the fuel door). It's gotta be an inherent design flaw. Either that or it was intentional to keep fluid from flowing out and down the side. The consequence is, water (or any liquid) will pool inside that cavity.....and in the case of water, cause rust.
I don't see why the regular cap won't fit your 09. You should be able to get one from a parts supplier or from the dealer parts counter. I've seen the one you describe, but as an aftermarket product. | 
