It is unlikely for sperm from intercourse on December 9th to result in pregnancy 9 days later. The typical lifespan of sperm is around 5 days, and the egg is only viable for about 24 hours after ovulation. However, every woman's menstrual cycle is different, and there can be variations in ovulation timing. If you are concerned about the possibility of pregnancy, it is best to consult with a healthcare professional or take a home pregnancy test.