it is possible but you would have to have voodoohda do a iopcimatch to the device id that you want voodoohda to hook to. it can be configured inside the voodoohda.plist.
you would have to change IOPCIClassMatch to IOPCIMatch then put the device id you want to hook to. so replace 0x04020000&0xfffe0000 with whichever device Id your HDMI is which you can probably get from DPCIManager app.
so applehda will take one device and voodoohda will take over the other.
but I do not know if whatevergreen.kext will interfere if you are using it.
also you would not be using the applehda disabler as that would kill applealc.
and voodoohda does not work with all HDMI. maybe the scenario is reversed and voodoohda is feeding the speakers not the HDMI but since he is running both I guess he has to look at what kext is loading what device. then adjust accordingly.
@ HaggisMaster:
My 9020 was having sleep issues similar to yours. I went in energy saver settings, and there was a setting I had not seen before, "Power Nap".
I removed the checkmark from that, and Sleep/Wake has been working like normal.