It is certified in EV8 SP3. If you look in the updates.htm there is the following section :-
Microsoft Entourage 2004 version 11.4.0 or later
Microsoft Entourage 2008 version 12.1.5 or later Enhancements to the Enterprise Vault Client for Mac OS X
You can now use the Enterprise Vault Client for Mac OS X with either of the following versions of Microsoft Entourage
I see what you mean in the compatibility charts with regards to the MAC EMAIL CLIENTS section but on the next page you will see the Legacy MAC client support and Entourage is down as Yb, with b being a footnote stating that EV8 SP3 is required.
With have a word with the documentation team as this is a bit confusing in my opinion.