According to Official Guinness Records,
At 21 years 10 months 5 days, Sidney Crosby (Canada, b. 7 August 1987) became the youngest captain of a Stanley Cup winning team when the Pittsburgh Penguins (USA) defeated the Detroit Red Wings (USA) in the 2009 finals.
For a complete list of 2009 records, please visit 2009 Guinness Records in United States.