It's in WebLink 9, as you noted, and it will also be included in the next version of Web Access. We don't currently have any plans to add media streaming into the desktop Client as it can launch already launch media applications directly. 

Whilst the desktop client might already be able to launch media applications directly, before the desktop client can allow a third-party application to run a media file, for example a MP4, my understanding is that Laserfiche must at first export the file, which can take some time for very large media files.

The purpose of my original question was to establish when video streaming functionality is scheduled to be made available within the core Laserfiche desktop client. Inherent within the question is that is is streaming functionality that is required, i.e. without the client exporting the file.

If I have missed something and it is already possible for the desktop Client stream media files, e.g. MP4, without the file having to be exported, please can someone tell me how this can be achieved.

There are no current plans to add this to the desktop Client. 

Can you tell me what version of Web Access media streaming will be available and what is the timeframe for release of this version.

It will be present in Web Access 10, currently slated for release this fall.