I am certain that any intelligent species can only exist as a direct or indirect result of evolution. They must have either evolved or been made by entities that evolved. Given that basic premise I also think that it is inevitable that memetic evolution will have occurred. Ideas will have spread because communication is inevitable within an intelligent species. Ideas will spread because the vectors for those Ideas feel reasons to spread them.
Religion is inevitable once a base level of communication skills and intelligence has been achieved.
The memetic adaptations required to keep an idea going within a particular community will arise. If the community has an IQ of 80 then a simple religion will emerge with simple memetic hooks, simple rewards and simple defences against contrary ideas. If the community has an IQ of 180 then the brighter minds will be able to come up with better ideas, more fiendishly complicated religions with more cunning reasons to believe in them. Ideas like the afterlife, religious tolerance, freedom of expression, faith. I see no reason to believe that brighter minds in a brighter community would not be free of religion.