A few days after release Firefox 9.0 Mozilla has released a sudden update due to various bugs found within hours of the release.
Firefox 9.0.1 fixes some problems reported earlier by users Mac and since it was seen that the fix that bug also solves some problems for Windows users, It was decided to make available to all the new version.
For users Linux so there are no problems and then can easily maintain the 9.0 version.
In this page you will find the release notes of the new Firefox 9.0.1.
Firefox 9.0.1 is already available for Microsoft Windows and Mac in this page you will find links to download.
Firefox 9.0.1 is also available for Linux but in the end, the update brings no improvement over the previous version.