It depends...
First of all, for an IMG is not good to apply without all the exams needed for certification, and it would be even harmful if one of those is just a 'fail' without successful second attempt in your transcript.
If you think you can overcome your CIS issues in 2 weeks, get a test date and definitely pass this time, the current testing period lasts until Sept 7th, so you can still get your result for Oct 9th, let's say middle of October. So you would still be on time to get some interviews (most programs fill their interview slots by the end of October). Now this would indeed be a risky bet.
If you feel you cannot overcome your CIS issues and get a date until Sept 7th, then your score would be reported in December, which is almost the end of the most active phase of the interview season. It would be crazy to apply then. If this is the case, just take it easy, take a live course for CS, do observeships, or Step 3, and apply next year.