There is a big difference in interests, from 4 to 9 years old.
The older girls, (if they are like my 8 year old Daughter and Friends), they are pretty independent.. and do their own thing. Not as structured things.
For the younger girls, they like maybe Princess things? Still?
www.orientaltrading.com has TONS of party stuff/goody bags/games and in bulk prices. Economical.
My daughter, likes Pinatas.
And 'treasure hunt' type games in which they can find goodies. Which you can also get from Oriental Trading.
Jewelry making, will be more for older kids.
The 4 year olds, don't have the dexterity for it, by themselves. The Mom will have to help them do it or make it.
4-5 year olds, need assistance with activities or supervision.
6-7 year olds, have better dexterity and ability to follow direction and more complex 'games' or activities. More independent.
8-9 year olds... can do MUCH more, on their own, or with minimal assistance and supervision, per games/activities.
Rub on tattoos are also fun. Oriental Trading has that too.
Or, egg on a spoon games... them putting an egg on a large spoon and balancing it while they walk fast/run to the finish line.
Just look at Oriental Trading, they have lots of games.
good luck