I am reviewing the source code for the plugin and I don't see any way to set a post to be excluded from Swiftype indexing. It appears to me that there are no available filters which would provide access to a developer to extend the logic that determines if a post is indexible. I would like to see a filter in the Swiftype\SiteSearch\Wordpress\Document\Indexer\shouldIndexPost method which provides a means for controlling if a post should be indexed.