It should work... But having said that, El Capitan is still not at final release, so we might yet be broken by updates made available after Fusion 8 was finalized. (I believe installing the very latest El Capitan beta as a guest is broken on Fusion 8, for instance...)
What problem or symptom are you observing? At what point does it fail? What is the build number of El Capitan (e.g. "15A215h") you have installed on your host?
Cheers,
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Darius