I'm sorry, nice try. But shoot,
I can catch arrows, too. You use flu-flu fletching and fire at about 100mph with an underpowered bow, and catch at about 80mph. In fact, your link even lists the speed of the tennis balls as 85mph. That's nothing. A war arrow is going at about 250fps to 300fps from a decent bow. That's about twice as fast as the arrows used on mythbusters. There's also tricks about deflecting first and such, but I won't get into that.
You can make the argument that someone would get lucky, which is highy suspect even if you don't consider that in actual combat, arrows come in volleys, not singles, but people generally look down on lucky coincidences in books. Enough about that.
Prophecies:
I'd rather see less of the sort of prophecies that are so specific as to allow them such easy outs. Very few real prophecies were set up like that. In fact, I can't think of
any.
Also, such easy solutions are boring. There's no tension if you can just cut down the tree. Now, castrating yourself would make a great internal conflict. I'd love to see that in a book.
As an example of averted prophecy, GRRM has a prophecy that doesn't come to pass. I won't specify to avoid spoilers.
