9.30am  
 I would like to start at 8.00am but not sure if the custys would like that
Won't know until you try bud. 
If you want to start earlier-just go for it. 
I'd say avoid mums on the school run between 8-9 though. 
Old people are normally up early. 
Or the ones that are still in bed at 10am. 
I clean a few like that (night workers) just be quieter doing their bedroom. 
Over the course of a week you could end up with an extra half a days work done...
You only need (say...) 10 houses a week that you can start at 8 on.
I've got houses that I start before 6 on. 
It's just finding those that don't mind you getting there early.