Well... you know your child best -- how much sleep does she need? Just do the math and count backwards and you'll get your bedtime. Since it's all-day K, count on an extra hour of sleep at least for the first few weeks/months.
My oldest had his lights out at 8pm in kindergarten (he woke up at 7am and walked out the door to the bus stop at 7:45am). This past year we moved it to 8:15pm (2nd grade) and will probably keep it there for awhile. He needs at least 10-11 hours of sleep a night or his ADHD symptoms go through the roof and he's out of control the next day.
The next oldest starts all day kindergarten this fall. She is currently in bed, lights out, between 7:45pm and 8pm. We won't change it but will probably work toward the 7:45pm time more. Right now, it's 7:45am, she fell asleep at 8:05 last night and she's still sleeping. She needs a good 11-12 hours of sleep at night, especially when she's had a busy day.
I know from my son that full day K wears kids out... he was often in bed by 7pm the first few weeks of school until he got more used to it.
When you adjust it, do it in small increments like 10-15 minutes -- both for bedtime and for waking up.