I did as you mentioned, just YaST has some problems. When I open runlevel configuration the mouse show the usual clock as if something is loading and thus I cannot change anything, basically it freezes. BTW lm_sensors show "no", but still work normally anyway.
Did you copy /usr/share/doc/packages/sensors/prog/init/lm_sensors.int.suse to /etc/init.d/lm_sensors and activate lm_sensors in Yast ---> System ---> Runlevel editor
When you ran sensors-detect it would have mentioned a setting to be placed in /etc/modules.conf which in SuSE 9.1 is actually /etc/modprobe.conf The setting may or may not be in the file already. Just to a search to make sure the setting is there.
Also have a look in /etc/sensors.conf as there are settings in this file for your chipset which may have to be tweaked. The file is quite well commented.