Freeware for Solaris has a pre-compiled version of BIND 9.4.2.
Just pick SPARC or X86/solaris 9 and then scroll down.
Instructions on how to install are on the left column. (downloading/installing)
It may load the application in an unexpected path , i.e.: /usr/local/sbin/
so you may have to start the daemon from there. Solaris 10 is different.
Hope you know how to set up your data files. If not, you really need to brush up by reading.
I perefer the O' Reilly book: DNS and BIND minimum 4th version by Albitz and Liu.