If the sessions being killed are normal desktop login sessions then the dtlogin daemon should start a new X server for the session. Make sure that you have the most recent dtlogin patch installed. For Solaris 9 on SPARC that's patch 112807-17.
If the sessions being killed are some other kind of session, perhaps CAM or NSCM,
then make sure that you have the most recent SRSS patches installed or, even better,
upgrade to a newer release of SRSS. 2.0 is old; 3.1 is current.
OttoM.