WP Data Access has been tested with WordPress 4.8.3 up to 4.9.1 on Linux and Windows
Yes! Keep in mind however that WP Data Access creates a repository on plugin activation. If the plugin is networked activated on a multisite installation a repository is created for every blog. For blogs added later however, the repository cannot be created automatically. In that case the admin user of the blog will see a link on the plugin page which guides the user through a manual installation of the repository for that blog.