You probably could guarantee a profit if you got a perfect match on 0-0. Bahsedeger.com offers odds on "no pen", but you'd also have to back a small amount on "first pen missed" as well in case a pen is missed and it finishes 0-0 because you would win your bet.
Personally, I'd just hope for a pen. You need to manufacture a bet at about 8-1 or better I'd say to make it worthwhile. Bahsedeger offer odds of 1.15 on "No pen" so the inverse is 7.67 (20/3)