If we want to create dynamically created provisioning roles and account templates, can this be done through PX Policy?
There is no out of the box way to create these objects automatically. PX Policies can only be used to assign roles to users but not dynamically create new ones.
However, you can use PX Policies to make SOAP calls, which could be used to make TEWS calls back into your environment to create these objects. The design of the TEWS calls and PX Policy would be custom, specific advisement on designing such a policy would require a CA Services engagement.