I use the latest Version of CC which is 18.104.22.168.
I set the working space in Aftereffects to ACES or ACEScg (which ist provided by Aftereffects) with 32bit float of course. I then deactivate the “Display Color Management” and put a adjustmentlayer with the Fnordware OpenColorIO-Plugin over the compositin. This way everything below that adjustmentlayer is viewed through the RRT/ODT709 provided by OpenColorIO.
In some cases the Aftereffects color management can do the IDT to ACES or ACEScg. And if not possible I set the input to “Preserve RGB” and put an IDT to the footage, again through the fnordware OpenColorIO plugin.
The results get rendered out as OpenEXR-Files with the adjustmentlayer deactivated. Most of the time that layer is a “guide layer” anyways. So it’s not used on export.
So far that all works pretty well.