In my agreement my ex has the kids on Christmas Eve to celebrate his traditional Christmas and I have them on Christmas day. We have agreed that I will pick them up at 12 midnight on the 24th so that they can wake at my house and have a traditional Christmas. My ex has indicated that unless I do whatever he says over the next while that he will not allow the kids to be picked up at midnight but rather 9 am. He claims that this is his decision to make and not mine. What is my legal right in this matter? Does the day start at 12:01am?

Mostly it can start either at midnight or in the morning. Does your agreement alternate between years like odd / even fashion ? If it were that much of a sticking point then you should have clarified it to the courts. As of right now you could be back in court again over something that isn't considered a big issue.

If your written agreement does not specify, both are correct and will depend on what the two of you can work out.

** it is sad that he and/or you are still using kids as a tool against the other. This is not good on the kids at all.

Yes you are correct Fr_Chuck . I did finally get in touch with my Lawyer last night as she was in mediation all day. As it turns out even though the kids would like to be with me in the mornings it is the between the parents to agree on a mutually agreed upon time and the fathers decision in the end because he has them on Christmas Eve was that I will pick them up In the morning. Sad part is that the kids will not be attending Mass with me as their father is not a church going person. I would have thought that a 52 page separation agreement would have covered everything but as I'm finding out there are so many grey areas that you don't discuss with your lawyer during the rather hectic time of separation.
We will be opening presents with the children on the morning of the 24th and celebrate Christmas with family and friends on the 25th. I suppose it will work out just fine.
Thanks for your answers and I hope that this may help someone in the future.