So the first caveat is that any time you try to change any habit, especially sleep - I always say you need to really commit to doing it every day/night for a full week before you decide it doesn't work. I usually always get results after only three days, but I do think you need to commit to it - and when I say commit, I mean, do not waver at all in your consistency- to a full week.
So secondly, the bed time. I'm sure everyone is telling you this but you really do need to move it earlier. Babies that age need at least 12 hours of sleep and unless she's sleeping until noon the next day, she's not getting it. Plus, a consistent sleep schedule, with a consistent bed time is one of the ways babies start learning to sleep through the night. You're onto a good thing with establishing a bedtime routine (bath, nursing, pajamas) and if you do the same thing every night before you put her down, it will help prepare her brain for sleep.
At that age, I was putting my son to sleep anywhere between 7 and 7:30 at night, depending on how his naps had been during the day.
The next kind of bummer is, until I totally cut out the night time nursing, my son didn't sleep through the night. Even when I cut it down to nursing only once per night, he would still wake up one additional time wanting to nurse, even though I wouldn't nurse him. But once I finally cut out all night time nursing, he slept through the night.
It's so hard to be brave enough to cut out the nursing at night. I worried terribly my son would starve! But I promise you, at 8 months, unless your daughter has a medical condition she needs to nurse at night, she can definitely go without nursing at night. My son was an on-demand nurser during the day, and even he finally got the hang of no nursing at night.
There are some great suggestions on how to cut out nursing at night. What I did was gradually reduce the time of each nursing session until I was down to four minutes, and then I would cut it out entirely. Start with one session, the one she nurses the least at, and cut that one out first.
So if she nurses three times a night and nurses, say, 15 minutes the first time, 10 minutes the second, and 14 the third - start with the second nursing time first. Reduce the time you nurse to 8 minutes. You can even reduce the time every two nights if you're worried. But then, once you get down to four minutes, just cut it out entirely. She'll probably still wake for that nursing the night you cut it out but just go in, rub her back and tell her it's still night time. You can even just rock her back to sleep if you need to. I promise she'll get used to it! Once you cut that one out, you can start on the next nursing time whenever you feel you are both up to it.
But that absolute key is consistency. If you're feeding her sometimes and not others, that's confusing and will only add to wake ups. And the earlier bed time really will help. Even though everyone in your house is a night owl, the baby shouldn't have to be. She can be a night owl when she's older, if she chooses to be.
Good luck