This is the big dream we all have and are waiting for (maybe?).
In latest 2.4 the closest you can get is to create Authorization Profiles via REST API.
"Authorization Profile API allows the client to add, delete, update, search and perform actions on authorization profiles. In this documentation, for each available API you will find the request syntax including the required headers and a response example of a successful flow. "
e.g. a POST to https://<PAN_NODE>:9060/ers/config/authorizationprofile
Log into an ISE node and check the built in API documentation for more specifics.
But the Policy Sets etc. are only possible via GUI.
In ISE the REST API is a bolt-on (afterthought). If done right then any GUI action should be possible via an API call. And this is because the application itself uses its own API!!! If you don't like the GUI then you have the choice to write your own app. Maybe there are plans to expand this. DevNet is a big thing at Cisco but it should not have to take years to accomplish this. I suspect that it would be tricky to retrofit ISE to be completely API driven.
