I have 2 8-yr olds. 1 stands, 1 does not. I much prefer the one that does not stand... SO much neater. I don't think you're neglecting him by not 'teaching' him to stand. Maybe he just doesn't want to.
Cleaning around the bowl isn't a real issue for me. I'll do it, no big deal. My issue is that he can't and will not stand and pee. He doesn't do it in public and he certainly will not do it at home. I don't want to force something on him but we are his parents so I feel there is a bit a responsibility on our part to teach him how to do this. And me being his step mom, I feel it isn't my place. I think I should just tell my fiance' to stick to his guns and do it.
I have two boys and we ask them both to sit down to pee. It keeps the bathroom much cleaner. When they are in public, they pee standing up, but at home, even my hubby sits down to pee. I think it is a family culture issue, so as long as he can pee standing up in public, it should save you from cleaning pee from around the bowl.