It's a pressed steel plate kickstand, which you might be able to form by putting in a vice and bending with an adjustable wrench, or hammering into shape. Problem is that many of these are heat-treated and pretty resistant to bending.

Consider making an adapter for between the plate and the frame. It could be as simple as a rubber or wood pad, or you might file a piece of aluminum scrap for a perfect mating surface on both sides (kickstand and frame).

BTW- you might not have to do anything, flat kickstands have been bolted to curved chainstays for about a century, so it isn't a new concept. Just be careful not to over-tighten and crush the tubing.