removing 9 inch brake drums from hubs

They are very likely swedged on. Look at the base of the wheel studs where they meet the drum. It they appear to have been "mashed" around the drum at each wheel stud hole, they're swedged on. Do NOT just drive the studs out with a hammer. That will ruin the wheel stud holes on the hub. Get a 5/8 metal cutting hole saw and cut ALL THE WAY through the swedge AND the drum just to the surface of the hub, then drive the studs out. The drums will now fit loose on the hubs, but they are hub centric and don't need to be swedged. They were swedged only to hold them on going down the assembly line.