You can send a custom job_id see this. But to if you are not sending a custom job_id you have to wait until the job is finished to get the id when the object is returned.
The JobId will be available as part of the metadata field in the Operation object that is returned from Instantiate operation. See this article for how to work with metadata.
The Airflow operator only polls on the Operation but does not return the final Operation object. You could try to add a return to execute.