My daughter went to nursery from 8 months old, for 2 days a week, (now 17months) and around the time she was transitioning would sometimes have 1 nap, lasting just 25mins! or not having a second nap until 4/4.30.
I did have to be quite clear with the nursery, that it wasn't strict, but she needed to be put to nap at a certain time, (before 11, their lunch time, in the morning) and no later than 3.30pm in the afternoon as it was affecting her bed time. Honesty is best with them from my experience, so they understand how it's affecting the rest of your DS's day.
As for the later bedtime, DD goes down at 7pm most nights now and sleeps until from 5.30am - 8am, but bedtime was about when she needed to go to bed rather than strictly at a certain time when she was settling into nursery - he's only been there a month, DD has just started getting into a nursery and home sleep routine in the last 2 months so 6 months after starting.
I would agree with other posters however that a regular 8pm bedtime is too late, just for the sake of DH seeing him. My DH takes DD to nursery on the days I'm working, at 7.20am, and doesn't get him until 11pm, so he sees her a total of 30mins each day, if that, two days a week.
Could your DH take DS to nursery or get him up and give him his breakfast to spend the time with him in the mornings instead of it being after he's home from work on those days??