I think there's a difference between believing in the possibility of a higher power and being religious.
I am absolutely not religious in any way shape or form. No 'Abrahamic' god can possibly exist in my opinion.
That said, I see no reason why a 'non-interfering' deity can't exist. By that I mean, a higher power who is a creator and nothing more, simply a catalyst for all that came afterwards. You can't pray to it and it doesn't set rules for you to live by, it just 'is'. You could say 'god' in that sense is just a metaphor for something more scientific such as the quantum fluctuation which caused the big bang. Or maybe just a thing that lives outside of our every day experience, in which case we can't possibly judge it.
I'm not saying I think that this is the case, but I would say that as long as there's a small chance of it being possible then we mere mortals can never be absolutely sure.