Can I run heating duct work through the attic?
I can't think of any reason not to run the duct through any open path. If the duct goes into any uninsulated space, you'll need to have the duct itself insulated. And on a vertical run between floors, I like to have a fire block between the floors, but that may not be code in a single family dwelling. Be sure to block any drafts, run a vapor barrier, and insulate where the line goes from an interior wall into the attic space.