My GD has been diagnosed with Global Development Delay. She spent as extra year in Nursery (as an August baby this didn't present too many problems). Now in Reception, although she is progressing nicely, the staff are giving her extra writing and lessons, while the rest of the class are playing. As a result, she turned round to my daughter the other day and said that she didn't want to go to school because she didn't want to write, she wanted to play! D went and spoke to her teacher, who was understanding fortunately, but we have yet to see any difference in GD's attitude to school as she has been sick at the end of the last week, so hasn't been in!
She also has school set homework - exactly the same as other pupils. Most of the time, D ends up doing the homework with her - but writing the answers for her! And some days GD is so tired, it's all she can do to eat and fall into bed!
I would echo what many said here - let infants be children for the first few years, by the time they hit 9+ is plenty of time for them to consider homework as the norm.