Packages for the release of KDE SC 4.9.4 are available for Kubuntu 12.04 and 12.10. You can get them from the Kubuntu Backports PPA for 12.04 and from the Kubuntu Updates PPA for 12.10.
Bugs in the packaging should be reported to kubuntu-ppa on Launchpad. Bugs in the software to KDE.
To update, use the Software Repository Guide to add the following repository to your software sources list:
12.04:
ppa:kubuntu-ppa/backports
12.10:
ppa:kubuntu-ppa
Or, from your konsole:
sudo add-apt-repository ppa:kubuntu-ppa
Thanks to Philip for his work on these packages