Anonymous Monk,
I am a bit confused. Since kill -9 is "untrappable", it will surely get results though there may be undesireable side effects. I do not know what, if any, cleanup your process would need to do to cleanly exit but kill -9 is friendly. Did you attempt restoring the old signal behavior by setting the environment variable and it didn't work? Perhaps it is something that is beyond your control - more information about your specific situation would help us help you.