Hello, Unprotected sex on 9th day of cycle is very much safe if previous cycle was regular. In addition, unwanted 72 gives extra protection against pregnancy. You may get a withdrawal bleeding within 7 days and next period may be delayed or earlier due to hormonal imbalance. Here, chance of being pregnant is almost nil. Normally, you get period 28-30 days interval. Pregnancy depends on proper timing of ovulation & unprotected sex. Ovulation occurs just 14 days before the due date and fertile days are 3-6 days around ovulation time. You can use ovulation prediction kit to predict ovulation and prepare for sex. Avoid stress/ anxiety, take healthy diet with Vit-E & Folic acid supplements, control body wt, need proper sleep & maintain personal hygiene. Be well & take care.