It's okay for your 8 year old son to wear diapers all the time.
All kids and all 8 year old boys should wear diapers all the time.
Yes your 8 year old son should wear diapers during the day and night.
An 8 year old should not be potty trained and should be in diapers and should be treated like a toddler as well.
At 8 years old the 8 year old boy does not have full bladder control and should be in diapers to pee and poop in instead and another benefit of the 8 year old wearing diapers or any kid wearing diapers is that they don't have to run to the toilet and instead they can just use the diaper and continue playing or doing whatever it is they are doing.
When I have kids my kids are gonna stay in diapers all the time as I'm never potty training them.
I wear diapers full time now as an adult and no longer use the toilet and that will be the same with my kids as there will be no toilet use in my house.
All 8 year old boys should wear diapers all the time and when at home the 8 year old should wear just the diaper and shirt and socks or just diaper and shirt and shoes like the 8 year old diaper boy below.