Leigh, you seem to have a cycle that is longer than 28 days. Do you have the time line right? It's now 16 days before your expected period, probably time for ovulation. Since sperm survive inside for only 5 days your sex from 9 days ago is not likely to get you pregnant, in fact that must have been right at the end of your last period. Some spotting at ovulation time is not unusual, though not the flow you describe. I don't think you are pregnant, but any unusual bleeding should be discussed with your doctor.
It is actually possible for it to be implantation bleeding. The second time I was pregnant I had implantation bleeding almost 12 days after. You can have implantation bleeding anywhere from 6-12 days after intercourse. So I recommend wait off to see if you miss your period you’ll know your answer! Good luck hun!