The fuel cap did change from 2008 to 2009. The 09 has a "screw type", as opposed to a "quick turn" type on the 08.
The 09 screws on like a ratcheting cap, except that when it's tight enough, the handle only turns the equivalent of one loud click and then stops. It's not like any other Toyota fuel cap I've seen in the past; my other Toyotas have had a screw-on ratcheting cap that lets the handle click and spin when it's tight enough.
I have never seen the quick turn type on the Tacoma, but I imagine that it goes on and turns less than one complete turn and that's it?
I don't know if the filler neck is actually different or not.