If I remember correctly the first swim is around 10:00 and unless you are at the park bright and early about an hour before it opens then you might have trouble getting into the first one since they fill up rapidly. Also, I can't imagine you would only want to stay that length of time it is such a beautiful park and there is so much to do.
In answer to your question though I would think it would be possible to be out of there by then and still do the dolphin swim.