Yader
Here's an easy way to burn in the Aces Look - save it as a default and you can render/save out jpg's/png's without going through COPs or a compositing app. First make sure you have the baked lut from ACES, it should be somewhere like aces_1.x/baked/houdini/ and it's called sRGB for ACEScg Houdini.lut. Load that into the flipbook LUT slot and turn Gamma either off or set it to 1 (doesn't seem to make a difference). Save as Default and hit Start. Oh, and your viewport should be set to Karma of course 
Maybe some guru can chime in and help out with an expression for a timestamp in the filename.
So now, every time you create a flipbook you'll get the look from the viewport burned in.
This works from the Export > ffmpeg mp4 that's built into mplay as well, but you need to set the inverse sRGB gamma of 0.454 so the .jpgs it creates as temporary files don't throw off the LUT with a double sRGB conversion.
It appears that the dialog for this is missing the option to disable the "conversion to the image's native colorspace" that is available in the Save frame as dialog.
I really wish Houdini would save defaults for everything btw, if I had a dollar for every time I had to constantly set various UI things I'd be a rich man

Not sure how accurate it is with that value in the ACES world, but it's close enough for a preview.