The cat is telling you that it may be your house and your shoes, but it is HIS territory. If you go to a pet store you can buy a bottle of liquid that neutralizes cat and dog pee odor. I'd give the shoes a good soaking in that, then wash them.
Aw come on now!!!! I just got back from Galveston a few days ago and left my dive boots and wading shoes just laying in the bed of my truck. A lady down the street from me has been feeding some stray cats and I occasionally see them in my yard. Now I guess I'd better go get them.