OP - If your clearance is for CTC only then they won't do a credit check. If it is for SC then they will, however this doesn't mean you will fail. What you must do is be totally honest - if you lie then you will be rejected. If you tell the truth & explain that you are taking steps to deal with your debt then you stand a good chance.
You may find they come back to you for more info - don't be worried they have a job to do. What they are looking for is why you got into debt - they would have concerns if, for example, it was for compulsive behaviour such as gambling, drugs etc, however again, if these are the causes & you have shown that you have dealt with this you would still be considered.
They are also looking for honesty & integrity so that you are not open to bribery, extortion or espionage.
You will probably get sent an extra form to complete, which is a financial form - again be honest as if you don't declare everything your credit check will show it.
You will only get your friends/family interviewed and very personal questions asked if you are requiring Developed Vetting, which is much heavier stuff, as Melanie rightly said!
Good luck
