I have enabled the VPA on cluster as read only mode and tried to collect the VPA recommendation data. But I could not find a good documentation or any API details specific to the Vertical Pod Autoscaling. I have found it for the Horizontal Pod Autoscaler but not for the VPA.
I endup doing little different way. I used GVK API to query using custom object API. I listed all the namespaces using corev1api and then did
list_namespaced_custom_object(group="autoscaling.k8s.io", version="v1", namespace=<namespace-name>, plural="verticalpodautoscalers")
Python library example is here
As I mentioned in comments
From what I see in the python client library, there is neither documentation or API created for Vertical Pod Autoscaler at this moment.
There is only documentation and API created for Horizontal Pod Autoscaler. Which may be found here.