First, I think it's wonderful that you are getting the green-light to try for a baby! Extra wonderful after a struggle with Crohn's Disease!
I'm not sure why your doctor is concerned about tearing not healing... do you have issues with wound healing? Anyway, I always err on the side of trusting my doctor, since I'm not an expert. I had 3 caesarean-sections myself. Not due to my Crohn's but due to my babies all being breech. I loved my c-sections. They were calm and quick procedures. Healing took a while, but it just meant no carrying anything heavier than my baby, and it was a bit of a trick to sit-up in bed. Pain when coughing. But it only lasted a few weeks.
(Most light exercise is ok when pregnant if you check with your doctor. I liked to go for walks myself.)
My c-section scar is below the waist band of a pair of bikini panties. So, no one would ever see it. It has faded quite a lot in the year since my last baby. Although I'm sure it will always be there.