Pre flowers

I have plants starting to show their sex and I am fairly sure one is male. I haven't put them on 12/12 yet so would it be safe to wait a couple of days just to be sure before chopping him down? Can they pollinate while on 18/6?

I would wait a few more days. I don't think they will polinate until at least several days after they show their sex for sure. It takes a little while, but I would check it every day just in case.