Its preferable to use spark streaming (with Delta) for batch workloads rather then regular batch. With the trigger.once trigger whenever the streaming job is started it will process whatever is available in the source (kafka/kinesis/File System) and ...
Yes you can create a "Single Node" Cluster, https://docs.databricks.com/clusters/single-node.html . It is currently not recommended to use "Single Node" cluster for streaming workloads
