I am familiar with David's work and insights and despite our current understanding, it would be entirely plausible for a rational empirical person of the time to believe in God. All that we can know clearly comes from our senses. However, it is a modern understanding that we cannot know God via our senses (or any of the tools we build to bring data from outside our senses into the range of our senses). This understanding is borne out of the absurdities of religion in contrast to the functional wisdom of science. Previously it was thought that the Arguments of First Cause and certainly the Argument From Design showed the handiwork of the Lord clear as day. Likewise as Hume conceded the argument from Design in Dialogues he may have done so in life as well. As a number of good freethinkers from the time were deists, this is not a far-fetched notion. I count Jefferson among the great thinkers and he, like many of his intellectual rivals of the time, were deists. Jefferson lamented against "invisible Gods" and thought supernatural Gods were talks of nothing and clearly atheist as D'Holback and markedly more absurd.
So, no. Today David Hume would almost certainly be an atheist, and, admittedly, it would be evolution which would assure that result. Intellectually honest skepticism no longer gives rise to a rational deism; atheism, since the time of Darwin, has been the typical end point to a functional epistemology. It is entirely possible, that, in a historical context Hume was a deist. -- Admittedly since the Christians would have murdered Hume for outright atheism, there is a justified belief that had he been an atheist our understanding of the man would be identical to our understanding now. However, you cannot apply the understanding of today to the intellectuals of the pre-Darwinian world.
Damn... look how smart I am.
LOOK DAMN IT!