I think it's probably a good plan to take your son to the sitter and have your mom pick him up. I wouldn't have him see you and the baby in the recovery room. It will be way too overwhelming, and honestly, you don't know how your delivery is going to go. It might be pretty upsetting to him to see you just out of surgery. Plus, I don't know if the hospital will even allow him in the recovery room?
When my parents brought our son to see us in the hospital room, we made sure that I wasn't holding the baby. I wanted him to be able to see that I was still available for HIM. Also, we had the baby get him a couple of presents, so we brought those to the hospital too. Honestly, he was more into the presents than the baby, but 17 months later, he will talk about things that happened in the hospital room that even we had forgotten.
Prior to the baby's birth, some things that we told our son was that the baby was our present to him. Essentially, she was going to be HIS baby. This may not be an option for you, but our son pretty much named his sister, so he's been emotionally invested from the get-go.
The day that I went into the hospital, I just told him that I was going to go to the hospital and have the baby. I said his grandma was going to do bedtime with him. I called him on the phone from the hospital before bedtime so that I could sing his songs to him and tell him I love him. The next day, he came to see us. He did another bedtime with grandma, but we came home that night and were home when he woke up the next morning.
Good luck! I'm sure it will be great.