There are several, very different Hollywoods to see.
For children the ages of your daughters, I think Universal Studios Hollywood would be all they really understand. Theres plenty to do at the theme park, they get a peak at a real studio (rent Back to the Future before you go so everyone recognizes the town square set) and CityWalk has enough dazzle to keep fill in for all the glamour real Hollywood doesnt have.
The Hollywood and Highland complex is nice, but it is essentially a shopping mall. The highlight for movie buffs is the Kodak Theater. Its the home of the Oscars. They have a good tour of the inside And for a limited time up to ceremony, theyre running an Oscar promotion that lets you hold and be photographed with a real Oscar.
Part of the complex if the Chinese Theatre and part of the Walk of Fame is outside as well. Over the last couple of years, however, this area has become infested with street performers dressed as various movie characters. Theyll pose for pictures and they expect a tip. There have been problems with them becoming a little too insitant about the tip. The people are hired by anyone, they just show up (its freedom of expression according to the courts). The whole thing is rather seedy.
Across the street is the El Captain Theater. Like the Chinese theater it is an oppulanent movie palace thats worth a visit for movie fans. Our grandparents didnt have DVDs, but they sure knew how to see a movie. The El Cap is the flapship theater for Disney check if there are any special programs during your visit. Disney tends to put on a good show.
The two other Hollywoods working Hollywood and the nightlife/club scene Hollywood probably arent of interest to nine year olds.
In general, theres not a lot to actually see in Hollywood. The town itself is long past the glory days and the current hot spots do not cater to tourists.