Did the Haitians actually attempt to strike a deal with the devil? If so, I can see him making these comments. If they didn't it's a stupid thing to say. And the timing isn't that good either.
Leaving aside the hilarity that you're actually willing to believe this at all...
How exactly would one go about proving or disproving making a pact with the devil? Don't you think if the historical pre- and post-independence documents of the country and its leaders contained references to "Made deal with Satan today" that might have caught someone's attention by now?
Would you still hold all of the numerous generations of Haitians since such a pact with Satan responsible for the alleged sins of their ancestors?
Who does Robertson think they need to turn to, since the population of Haiti is overwhelmingly Christian already?