8 year olds are starting to want to separate themselves from their parent - they are their own person - (grin). Seems pretty normal to me. But the "hold on" "just a minute" stuff makes me crazy. Could be she hears you and your husband saying the same to eachother? Explain why parents may say this to eachother (we're in the middle of another chore, etc.) but that when you need her to do something unless she's in the middle of something you need her to respond now.
As for the laying down with her at n ight - I did that with my now 14 yr old daugher until only a year or 2 ago. I found it was such a special time to hear about her day, when I could instill our values in to her life, etc. WE're in the midst of teenage stuff now but I think deep down she has a decent set of values based on all those hours over the prior 14 years that we'd talk in the dark about her day, her friends, stuff that's going on in the family, etc. funny that's when I was also able to begin our talks about sex. She didnt' have to feel embaressed, I knew sex-ed was coming in health class in the next couple of months and I wanted her to hear it first from me withour values. I wouldn't stop the bed time cuddling until she's ready to bring ti to an end. Think of the sweet memories she'll have of your talks and how secure she must feel. Regardles of what's gone on during he day she knows you love her and always will.
You know, when I was a teenager my mom worked midnights to support our family. (My grandmother lived with us and was home with us) I would wake her up at 9:30 to get ready for work. There were times when I knew she was really tired (becuase she was doing stuff for us kids when she needed to sleep) and I'll lay down in bed next to her to wake her up gently. Now that she's in her 80's and is dying on cancer I sometimes go in to her part of the house and lay down next to her and it brings back those sweet times when she sacrificed so much for us.
You can never spend too much time with your kids - especially at this age - this is when she's still listening to you and wants your opinion. The time will come when she won't ask your opinion and if you've already shared your values with her you can feel a little bit better that she's got your ideas in her heart & mind. Kids spell love as T-I-M-E.