Mormons are Christians, so no.
Not by the definition of most Christians, so he might have.
Please elaborate.
Most Christians don't consider Mormons to be Christians. What's so hard to understand? I can't give you a theological explanation, it is what it is.
Whether other Christians "consider" Mormons to be Christians or not is out of the question. Mormons are Christians. Period. The question was "Did Obama win Christians in Utah?" not "Did Obama win what non-Mormon Christians consider Christians in Utah?"