I've known people to get positives at 9DPO, but it is really early. Implantation may not have even taken place yet, and if it has it could have been within the past day or so which would lead to not enough hormone for the test to give a positive. I really think that it would be best to wait until at least 16DPO. Even early tests don't always give a positive as early as they say- they are only about 60% accurate before your missed period.
I do understand where you are coming from though! I've tested day after day with my last pregnancy until it showed positive! It's so hard to wait. But I also knew that I wouldn't be extremely disappointed if it was negative.
No matter what you do, I wish you the best of luck!