Sept my period date changed due to exercise. my date after was the 9th, this was the same for 2 months, it's 6 days after the 9th, my period hasn't come?

Possible: Excessive exercise can definitely result in a change in your periods. Oligomenorhea, too few periods, or amenorrhea, no periods can occur. I know this might seem like a nice thing, free of the hassle, but in reality there are significant short term and long term consequences. Your bone health is at risk.: stress fractures now and osteoporosis later. Could you be pregnant?

Still exercising? : Have you had unprotected sex? Are you exercising the same or more so than before? Do you have medical conditions such as thyroid disease or anemia. Are you suing contraception? Are you bulimic or anorectic? All these variables are necessary to be known to be able to discuss your question.