There are no humans on this planet, obviously, but could an ambush predator fill the same niche as a human did on Earth? I'm unsure if humans being pursuit predators actually mattered in our growth in intelligence, so I guess that's why I'm asking this question! Let's assume these aliens are also very social creatures, living in packs and whatnot. Could this also affect their future society?
As long as it is to the evolutionary advantage of the creature then yes, it could happen.
It makes sense that, for a predator that ambushes it's prey, it would be beneficial for a species to have the ability to work well together, predict it's prey well in advance and perhaps even create tools to assist. The more prey they can catch the better the mutation of this species will survive and so the more advantageous it is.
As for why greater intelligence would be an evolutionary advantage: Ambush predators could have used greater intelligence to improve their hunting techniques- traps, ranged weapons, and artificial camouflage spring to mind. In humans, developing tools (spears, atlatls, and such) made our basic "chase the animal until it collapses from exhaustion" strategy much more effective, so there's no reason that the "jump out at your prey from a tree/the water/etc." approach couldn't also be improved by basic tools.