I'm pretty sure that you can install the Compliance Content from BSA 8.9 into a BSA 8.7 infrastructure.
Download the BSA 8.9 files from EPD and follow the installation instructions
Only CIS Template for Microsoft Windows Server 2012 R2 was updated to Benchmark 2.2.0 in BSA 8.9
New updates for the following are expected to become available in the next few weeks:
Microsoft Windows Server 2008 R2
Red Hat Enterprise Linux 7
Red Hat Enterprise Linux 6
i'm not sure if the installer will let that work. there shouldn't be any engine changes (as has been the case in other recent releases) so you should be able to install to an 8.9 env and do the version-neutral export. just make sure to get all the EO scripts as there are likely changes there.
I've had a chance to check this a bit further - and Bil is right (of course)
The 8.9 installer requires an 8.9 environment.
It would be good to have an IDEA logged to request Compliance Content to be provided as version neutral ZIpKits