I have upgraded to Linux Kernel 3.9 since it was released few days ago and so far it was working nicely here. The only reason why i didn't post anything about this update is because VMWare Workstation is not working anymore after the upgrade.
Let me be clear about the situation. The problem is not due to Linux Kernel 3.9, but more to GCC 4.8 which is now included in Slackware-Current. Linux Kernel 3.9 ships more VMWare components (vmci and vmsockets) into the main tree, so VMWare products should be more compatible on Linux platform, but since GCC has became more strict, some problems arises and i still don't have any solution for this problem as for now. I have been searching for clues and patches, but no luck. Probably not so many people uses VMWare Workstation and GCC 4.8.0 combination.
Linux Kernel 3.9 works nicely with NVidia driver (both legacy and current version), so if you don't use VMWare products and only use NVidia GPU, you are safe to upgrade to this version.