Theres no way you would feel a shock off 9V.
And Zorg I dont think anyone ever died from licking a 9V (maybe they died while licking a 9V, but not killed by the battery itself.)
But inventing a story like that may stop a few kids licking batteries. So its a good thing.
Techincally its possible to be killed with a few milliamps of current, but people are resistors to electricity, so it requires a voltage at least in the hundreds before you get current anywhere near your vital organs.
Maybe if you connected 2 razor like prongs on the 9V, and stabbed them into your heart or brain, you would die. But again Id argue its not from the 9V battery....
Incidentally, when you put a 9V battery on your tongue, the tingly feeling you get is not electricity passing through your tongue. Its actually the taste of the salt produced by electrolysis of the salt water on your tongue....