The API only allows querying the scores of SCA by indicating the agent_id in the URL.
What you can do is generate a script with some language that you handle (as an example you can use python), where you list all the agents by using the API, you can use the following URL:
https://<your_ip>:55000/agents?select=id,name
Then go through the result and for each agent execute the score query:
https://<your_ip>:55000/sca/000?pretty=true
Or just the score directly:
https://<your_ip>:55000/ciscat/000/results?pretty=true
I hope to be helpful.
Thanks.