Looks like this is your first post, so Welcome to Genvibe!
I'd bet money they are Toyota, and that the same ones are used in many Toyota vehicles. You might be able to find some generic fasteners that will work in a chain auto parts store. Or perhaps try hitting one of the online Toyota Matrix parts web sites, for example
https://parts.olathetoyota.com/v-2009-t ... sh-shields can get you the Toyota part numbers for the 09 Matrix splash shield fasteners.