I am working on this right now, hopefully it will be available in the next version of the plugin. Will keep this ticket as not-resolved until the code gets merged in the master repository.
Speaking of whitelisting how about changing the current wp-content 1-click hardening htaccess file code to this code in the link below and then add a form with db options that has a text/text area input field where users can whitelist plugins by plugin folders or individual plugin files. If you use a text area form input then the whitelist rules could use this format: /path-to-plugin-folder-name/plugin-script-name.php, /path-to-plugin-folder-name/plugin-script-name.php and then you would explode/implode to handle/process the whitelist rules.
https://wordpress.org/support/topic/sucuri-1-click-hardening-wp-content-htaccess-file-problem-detected#post-6087304
I will move this to our internal tracking system and will discuss with my coworkers, if they agree to include this feature in the plugin then I will release it as soon as possible (hopefully with the next version).
