I agree a bug bomb would not be ideal, but if you must, I would take off any hob filters/skimmers and remove anything that might be sticking out above the top rim of your tank. Seal it up as best you can with a trashbag or some sort of plastic sheeting and seal it with duct tape. take all removed components and equipment you ever put in your tank (hoses, nets, etc.) out of the blast zone. Then bomb away. Those things take about 3 hours, right? I feel like your tank would be fine being sealed up for 3 hours, but I am not sure. I'd most worry about the oxygen getting depleted, but then again fish get shipped in sealed bags, so maybe it's not a problem.
But yeah, get some powder.