my son was 2 yrs behind at that age, and diagnosed with (only moderate) dyslexia.
IEP's, and one-to-one twice a week, but no statement.
With support at home, some extra lessons (we tried Kip McGrath and Dyslexia Action) and a being quite pushy with the school, we got him up to a level 4b for his current Y6 SATs, which is an amazing achievement for DS. He is so much more confident too.
DS was just not really "ready" for school until he was about 9/10. If I and known he would just click later, and catch up (he made 4 sub levels progress in Y5) I would have been less stressed.
I think it is good to consider all options. You know your son, and what is best for him. Also, no decision is for life. You could try Home Ed for a year, and then decide if you want to continue.
I think that there are a lot of children, especially boys, for whom the current education system just doesn't work. Too much sitting down, and listening to instruction. too much written work. Not enough hands on, active, engaging stuff. Why can't they MAKE more stuff, get out and about more, forrest school style. A lot of kids learn from doing rather than being told about things.