I looked it up and found that Viktor Alexandrov is the youngest player to do it. It happened at the 2001 tournament and Viktor turned 15 during the tounament (b. Dec 28/ 1985). He scored 2 goals and added 1 assist during the tournament. He played for Kazakhstan which is probably why no one knew about it since they are not a top team. Kazakhstan got relegated and hasn't been back since. However, it is Viktor Alexandrov who holds the record.