How long for a 9 year olds party?

[Holidaycheer]

We are having a party at home for dd and about 3 of her friends but as my dd has additional needs we haven't been able to do the whole party thing before so I'm unsure how long or what times will be best? We were planning on a Saturday and I was thinking 11am-6pm with lunch and tea included. Is that too long or awkward timing?
Alternatively we could do a 3 hour party but would need to include 'lunch' type food.
I want to maximise the possibility for the other children to be able to come as it's a big deal for dd, she's struggled to make friends until recently and has missed out on parties/play dates and discos.

11am to 6pm at your home sounds really long to me - I’d go for the 3-hour timing instead.

What are you planning to do at home apart from eating lunch and dinner?
I dont think 7 hours is too long for four 9 year olds provided they have stuff to do. An I actually think long parties are much less awkward as I can go somewhere and do stuff with my other kids.

Oh God, 2 hours max for a kid's party. They're exhausting...for the kids too. Especially if you are having it at home. You need an activity, allow half an hour for lunch, then send them all in their merry way with a party bag. 7 hours!!? Are you nuts woman?! You'll kill yourself.

3 hours max.

Just done one - I tried hard to avoid it but was strong armed by friend into womaning up. It was actually great but bloody hard work.

We did:
Arrive, arty activities like painting & beading.
Pizza delivery. Everyone stuffed themselves.
Pass the parcel type games.
Cake.
Apocalyptic water balloon fight all over garden.
More party games as damp children began to be collected...

3 hours was ample!

Sorry should have added what we are actually doing! I've been looking at the details all day thanks to obsessed dd. We would have a science demonstration and two experiments to make which should take about an hour, then a leisurely lunch followed by a pamper party with sweet table for about an hour and a half. Then I was thinking a film/chill out and pizza before home.
I was trying to avoid it being an awkward time but don't want it to be either rushed or for others to find it too long.

Oh dear, you can tell I have no clue
Ok so 3 hours sounds like the better option, what time would you all say is best? Our lunch would be sandwiches, crisps, veg sticks, fruit platter and cakes. There will be plenty of sugar with the sweet table so thought a lighter healthier lunch would work best and means dd can eat the same as her friends.