If they have well-developed root systems, and it's that particular one, I'd guess it would be fine. Keep it well watered until frost and I expect you'll be better off than trying to overwinter it in their pots.

I planted a honeysuckle recently. I thought it might be too late at first. To give it some protection, I was advised to make a burlap windshield around it. Maybe this would work for your clematis too if you are worried about harsh weather.
Mika