I think it’s fine to use it!
[name_f][/name_f]I’m married to a [name_m]Damon[/name_m], and he’s heard the demon connection before, [name_f][/name_f] but only occasionally. I think there was even a video game he played with a demon character named [name_m]Daemon[/name_m] or something. There is also a vampire in Vampire Diaries named [name_m]Damon[/name_m], I think, which probably somewhat contributes for people. And I’ve heard the [name_m]Omen[/name_m] connection for [name_m]Damien[/name_m] as well, but I don’t think most people think of that. I don’t think very many people have even seen that movie since it seems like the horror genre is less common than other genres. There are some names that people have random connections to that they can’t unsee, but I think only a very small number of people would have that kind of association with [name_m]Damien[/name_m]. I also imagine that people think of demon when they hear it because of the movie. Especially because that movie is probably fading with time anyway, I don’t see it being a problem for a child born this many years later.
[name_f][/name_f]TL;DR I think it’s a great choice, and I don’t think the demon connection is prevalent enough for it to be a problem for him