I have an 8 and a 6 year old, so bed time happens at the same time for both, go up about 7.30, 6-year-old in bed by 7.45, 8-year-old can stay up a little longer, was 8.15, but she started to be hard to get up in the morning, so put it back to 8pm.
We don't have later bedtimes on the weekend unless we're out late or something. Would still be back and in bed by 9pm at the latest on those occasions.