I haven't experienced that exact issue, but dissimilar metals can get along just fine if they're handled properly (i.e., by coating the bolt's threads with anti-sieze compound.) Similarly, a coating of grease on an alloy seatpost will keep it from getting stuck inside a steel seat tube.

Back to the topic at hand - heating the bolt will cause it to expand, so you should try to cool it instead (or carefully heat the top of the kickstand.) I'd put the entire thing in the freezer for a few hours, then clamp the bolt in the vise and apply some heat to the stand. Work fast though, the heat will transfer to the bolt - hopefully the mass of the vise will slow that down. Good luck!