I can only say what I've personally experienced, so I'll write it down here.
The CF did a credit check on me, and it came back OK. The recruiting center told me this, plus my equifax report shows DND was in there. So my debt didn't cause them any worry, and they approved me so far (I'm still waiting on medical).
I have over $20,000 in unpaid debt. Four $5165.00 (plus interest) student loans, all defaulted. One $1000 credit card, defaulted, one $500 credit card, defaulted, and many many many (i have my credit report) late payments on rent, phone bills, internet bills etc....
I've had my own buisiness for 3 years, and it nearly bankrupted me. However, I told all of this in my interview, I was completely honest and candid, plus, before my interview I called most of my creditors, and told them I am going to start to pay off my debt. My $20,000 student loan debt is being handled by an extremely nice lady in the NS govt, collections, who said I don't have to worry about it and can start paying on it when I get in the CF. (I'm lucky that shes nice, alot of people in collections aren't).
My interviewer said they are going to have to check my credit, and I supplied the name of the lady in the NS govt handling my student loan. I can only assume they contacted her to verify my arrangement.
I have all of this debt, and the CF still approved me (thus far, still awaiting medical) because I made arrangements to pay it off.
Thats my personal experience.