1St time growing pumpkins and i heard you should roll pumpkins so you don't get flat spots. I'm growing Atlantic giants and when I was rolling the pumpkin the stem that connects it to the vine cracked down the center. Is the fruit still going to grow can I repair the stem some how or should I cut the fruit off and consider it a whoops?

The stem should still nourish the pumpkin but you have damaged the pipeline to the fruit. If this is your only pumpkin on this vine, leave it. If you are trying to grow multiple pumpkins on one vine, you can remove it. But I am the 'wait and see' type - I would leave it be.

At some point, the shape has been determined and rolling the pumpkin will not change that.