Both my kids were born before the 9 month mark!! Are they crazy asking this of you?! They must be, along with being massive CFers. Sod going through your husband re: communicating with them, and definitely sod allowing him to "do all the work". It would be a firm no from me. You need rest (and if you have your baby by then, believe me, you'll definitely NOT want a houseful of people having a party).
Like others have said, you need to start setting firm boundaries on things like this now. Here's an example of why it's important (sorry, it's long!)....
My (now ex*) husband one day came up with the "fabulous" idea of bring his DP (who lived about 30miles away) back to our place to stay for "a few weeks". Why? FIL had an awful chest infection. Now normally, I wouldn't hesitate to help/do what I can, but when I got to the bottom of it all, I found out that he'd seen a GP (after I'd suggested this to him about 10 days prior, when he told me he didn't feel great), had steroids and antibiotics prescribed...but then couldn't be arsed to take them as he thought he didn't need them.
He then got worse, phoned my XH and between them, they came up with the idea that PIL would come stay with us so that FIL can recuperate. I worked FT then (still do), was the sole breadwinner then (I still am), have 2DC (the youngest at that point was a poorly baby who didn't sleep properly). XH did the absolute minimum with the kids and around the flat. FIL was also a very heavy pipe smoker, and XH was willing to allow this to carry on in our home, "because it wouldn't be right to deprive FIL, whilst he's recovering". Oh and we lived in a 2 bedroom flat. XH said that PIL could have our room, and we'd sleep in the front room. MIL is doubly incontinent, FIL was also incontinent, both in poor health anyway. Anyway, XH told me of this plan....and I told him very clearly that if he brought them to our place, I'd turn them around and send them all back, and if he was that worried about them, he could go and bloody well go stay there**. I also spoke to FIL and told him to bloody start taking the meds (i.e. help himself) and see his GP.
*this sort of shit is the reason that he's now an ex husband!!
**now this goes against my nature normally. I'd do anything to help people, particularly family, and my upbringing always drilled it into me to be respectful toward my elders, and my husband...but it was the utter selfishness of XH and PIL that got me. FIL had seen a GP, got meds but then refused to take them. He then wondered why he got worse and expected to come to my place where "it's ok, TicTac is a nurse, she'll look after us all whilst I convalesce". The worse thing was XH didn't stop his dad and tell him no. He didn't stop to think that I was already working my butt off, juggling the DC (and dealing with him) and didn't need this on top of everything else. And stupidly, I felt so guilty saying no as it goes so against my nature. I remember being really upset and speaking to my mum about it, and she told me that I'd done the right thing, and that I had to put in firm boundaries on things otherwise they'd just walk all over me.