Hi RJ,
I understand your dilemma, having always been a working mother. I agree with most of what Abby S. has said. Although, I come from a culture in which eating dinner on the late side is normal; we've always eaten dinner between 7 and 8 or so. So, that's not an issue for me.
If I were you, I'd give your son a small glass of milk and a handful (in a bowl) of cereal or a few crackers when you get home from work. (Very small snack; enough to tide him over, not so much that his appetite is spoiled for dinner.) You can interact with him together in the kitchen while he's eating that and looking at a book or colouring or something and you're chatting and making dinner. Hopefully dinner will be ready just as your husband gets home. Then when your husband gets home you can eat as a family.
As to how/what your son eats, again, I agree with Abby. I think you should make one meal for everyone and your son can eat what he chooses. Maybe cap off his meal with something you KNOW he likes (an apple, a yogurt) so that even if he hasn't eaten anything from his plate he won't be absolutely empty at bedtime. Try to be calm and neutral, not anxious, about his food choices. This is hard for most moms (it always was for me)!
After dinner, bath and bedtime. He shouldn't have a snack, having had dinner so close to bedtime (even if he ate very little; this is how he'll learn to eat what he's given!).
I hope this helps and good luck!