"You cannot fly IFR in a Homebuilt PFA/LAA permit aircraft."
Not strictly true, you can fly IFR in VMC (in any aircraft). <pedant mode off>
In all other respects, wot ZA and Rod1 said.
In order to build an RV, you will need to be whole-hearted I'm afraid.
I see you have already moved from RV9A in the title to RV9 in the post - a most wise decision IMHO.