December 9 is the 343rd day (344th on leap years) of the year. There are 22 days remaining.
- 1594 - Gustav II Adolf, King of Sweden, also known as Gustavus Adolphus.
- 1608 - John Milton, English writer
- 1912 - Tip O Neil, Speaker for the US House of Representatives
- 1916 - Kirk Douglas, actor
- 1922 - Redd Foxx, comedian, actor
- 1928 - Dick Van Patten, actor
- 1941 - Beau Bridges, actor
- 1942 - Dick Butkus, Pro Football Hall of Fameer
- 1947 - Steve Owens, Pro Football Hall of Fameer
- 1957 - Donnie Osmond, entertainer
- 1958 - John Birch Society founded.
- 1990 - Lech Walesa becomes the first directly elected president of Poland.
- 1992 - Separation of Prince Charles and Princess Diana was anounced.
- 1992 - US Marines land in Somalia