Breakthrough bleeding 9 days after intercourse. could i be pregnant?

Pregnancy is always possible, but w/o knowing if the cited "9 days after intercourse" was the only exposure, or if ovulation took place at a coincident time in your cycle, it is not possible to predict the odds of pregnancy. If your next "expected" menses is delayed, obtain a serum HCG test 7-10 days after expected onset. If positive, see your gyn provider.