There are proponents supporting both sides of your question. And, one way to do that is to insist that it is done. He will be learning to take responsibility, but with some external pressures. As he gets older and his own sense of responsibility becomes internalized, he will need less parental insistence. When to begin homework each day can be a major consideration.
Some students prefer to get it done as soon as they get home from school.
Some families have their children do homework before supper, some after. A parent needs to keep in mind each child's workability timetable. A learning disabled, ADD, or ADHD child usually needs a distraction free environment and multiple sittings to accomplish all of the work. Sometimes working parents insist that homework is done at their convenience. For elementary aged children and some middle schoolers, that sometimes sets the stage for confrontation.