I've installed FP8 for Notes 9.01 and my tools have stopped working.

If you have recently installed a later fix pack for your Notes client.  Currently identified with Fix Pack 8.   You may experience problems with the Teamstudio tools not launching or working correctly.   With many of the later FP releases, IBM has been including processes in the upgrade that remove some Notes JVM/Eclipse based settings.   

As this is due to IBM actually making changes to the installed Notes client environment.   We are not able to resolve this specific issue and would require engineering changes on the FP being provided by IBM.

However, the workaround is to simply reinstall your Teamtsudio Tools as required.