As far as I'm aware, EV team takes about 90 days after the release of a product to complete the validation. Given that this is "just a CU", it may take less than that.
Exchange 2016 CU8 was released on December 19, 2017, hence I believe it should be validated very shortly unless there are some major changes within it.
There is no official response from Veritas on this, it is just based on my experience. Hence, I would suggest to wait for a little while and keep an eye on the EV compatibility chart.