Apple have released a free up-date for Final Cut Pro X that appears to be a maintenance release only.
I expect a major update to coincide with the release of The new MacPro in September so this release today is most likely just to bring things up to speed in preparation for the next major release – Final Cut Pro 10.1.0
The notes with the release of 10.0.9 are:
Addresses issues resulting in green artefacts when using Sony XAVC media
Fixes several issues related to interfaced media and retimed segments which could cause exports to fail. (This seems to fix those unexpected failures I have been having with clips that have some effects added)
Includes stability improvements.
This free update can be downloaded from the App store.
I await with eagerness the release of 10.1.0 – but expect it will be a full price upgrade as per the recent Logic Pro X release.