Most parts houses sell a repair kit that consists of a sleeve that bolts around the damaged area. And, depending on the size of the holes you might be able to temporarily plug them with a product designed to plug holes in mufflers. If there's a hole in the resonator or a muffler, you could first screw in a large sheetmetal screw and then use that sealant around the mostly plugged hole. Sounds real ghetto, but it's been done for years. . .Also, a muffler shop might weld the holes shut for a modest amount.

Duct tape will melt, burn, and after it gets wet (if it hasn't gone up in smoke) will just unravel, Plus, you'll have a pukey mess to clean off when you then repair it as suggested already in this thread. Aluminum tape is very thin and will not withstand high temps - it's designed to be used on HVAC ducts that rarely get over 100 degrees. Also, keep in mind that the closer you are to the catalytic convert. or the exhaust manifold, the hotter it gets.