It's actually only good up to 72 hours (3 days) after and, as Anonymouse said, the sooner you take it the better. I hadn't realized you'd said "today." Definitely go get that to try to avoid pregnancy. Please note it can cause some changes to your period for the month, sometimes making it come early or even late.
Starting the pill now or getting a depo provera shot will not prevent pregnancy (you have to use those measures BEFORE having sex), and as thatquietgirl said, if you do get pregnant, it could cause harm to the child.
However, what you CAN do is go to the pharmacy and get emergency contraception (also know as the morning after pill or plan B). It is over the counter now for people over 17, so you don't need a doctor's appointment to get it. The sooner you take it the better, but I think it's good for up to 5 days after you had sex.
If you can't afford to get pregnant, you should absolutely start using some form of birth control. I advocate condoms, since they protect against diseases (and some diseases can hide so well that your boyfriend wouldn't even know he was sick). The pill, the shot, the patch, the nuva ring, or a diaphragm (to name a few) could be added for extra protection. Keep in mind that you need to take the pill at the same time every day for it to protect you, so go for a patch, nuva ring, or shot if you think you wouldn't be able to do that.
If you ovulate before you get the pill or the injection (Do consider pros and cons, by the way.), you can get pregnant, yes, and taking pills or getting the injection can cause some problems for the unborn child. I'd make sure to mention to the doctor what happened before starting anything.
hello dear...im not n expert or what but as far as i know u cant do it...iean to have this contol pills or what after the act..since it only takes a couple of seconds for the sperm to get in your uterus or meet up with egg..it was your 9th day u say..well dear just hope for the best or u can wait for a week from today and have a home preg test...