We just did this for my 8yr old and it was great. We had 10 girls. What we did was first we didnt start the party till 6. I ordered pizza and had a movie ready. I put them in the floor let them eat and watch a movie. Lasted about 45min.
I went to the dollar store and bought bonnets and all sorts of decorations. I put them at the table and had them all make hats. This lasted about 30 min. I then took a big group picture. Sent my husband to CVS to print one for each girl. While he was gone we then made photo frames, also came from the dollar store. We then had cake and opened presents. At this pint it was around 9:00. Then I let them run around and play till 10. Then we pulled out the sleeping bags and put the rest of the movie back on. Made popcorn and they were mostly asleep by midnight. It was great. Then I took the picture and put in the frames for them to take home.
I was great and was so smooth, not but one fight the whole night. Good luck.