I am installaing RAC on Solaris 9, I want to clarify that I can use Solaris Volume manager.....One manual tells me I have to use Veritas Volumen manager, another one says:

Two volume managers are supported with Sun Cluster v3 for OPS/RAC:-

Sun's Solstice DiskSuite™ 4.2.1+
Veritas Volume Manager™ 3.0.4+ (32-bit Oracle), 3.1.1+ (64-bit Oracle)