S.H.
I assume you mean 9-9-10 :) (neat birthdate tho!)
The first birthday party is really for the adults. For my daughter's first birthday we just rented a meeting room at a park (she was born in Feb, so too cold to be outside!). The theme was Baby Elmo, so I got plates & napkins with that theme and then just used color-coordinating other items. We had some child-friendly snacks (teddy grahams, etc) and other snacks & veggies for adults. Also had a cake and then a special little cake just for my daughter (smash cake!). We had family & a few friends there and we just visited & ate, then opened presents.
If there will be a lot of kids of a similar age, you might have an activity for them to do. Depending on age, maybe you could have the party at a playground so they could play.