Moderate Risk Public Trust - Bad Employment History

I am in the process of getting a moderate risk public trust clearance, and am finally nearing the end of the process. However, I am somewhat worried about the significance of my work history. I have some good references, but I also had a few part time jobs in college that I quit after a couple days. I also wrote (mainly unpaid) for some blogs that were less than reputable and, frankly, ran by an unprofessional, mean spirited person. I included every job that I had in my work history, but I am worried about the possibility of that person being spiteful and bad mouthing me.

Basically, how important is the work history portion to getting a public trust clearance? I have no issues with credit, the people who know me well are childhood friends that are relatively high ranking officers in the marines, and no arrests or charges.