Is there a way to easily change an account to be a non login account (NP in the shadow) file?

I know I can just edit the file but that is not what we want to do. We use access control software and want to provide a way to set an account to be non-login using simple commands that can be mapped to a GUI.

I see that there is a built in command to set the password to be *LK* but that makes it so the cron wont run for that user, we still need the cron to run and the NP is the standard way to go.

Is there anything that can be done?

(I see it's passwd -N in Solaris 10 but we are still on 9, is there a way to get it in 9?)