Not really. It is not that you're more susceptible, it's that you are more likely to be treated with antibiotics because of your condition. As c diff is typically a post-antibiotic illness, you are more likely to experience it. But it's not directly because of crohn's.
Yes. Clostridium difficile risk is increased in anyone with abnormal bowel lining (crohn's disease, ulcerative colitis), and in any one who is immune suppressed. This includes the medications used to treat crohn's disease. It's very important to wash your hands regularly to prevent infections. Alcohol based cleaners (purell) do not kill c. Difficile spores. Soap/water is still the best thing.