Is there any way to query data from the unity catalog metastore using local spark?
Actual data isn't stored in the Unity Catalog - it's stored in the actual cloud storage, so if you have correct credentials, then you can access data using the Spark outside of the Databricks. Unity Catalog acts as a catalog for metadata about your data locations, schema, etc. And there will be an ability to use Unity Catalog via Hive Metastore interface - specifically done for external access to the data.