HC recently introduced LDAP and SitePro features in 9.21. Does anyone know about it? Or has anyone practically used these features  of Hosting Controller control panel?

SitePro: SitePro is a new integration done inside HC panel which is a professional website builder and can be enabled on any website inside HC panel. You can know more about it by consulting with the instructions as mentioned in below kb article:
http://portal.hostingcontroller.com/kb/a273/how-to-configure-sitepro-website-builder-with-hosting-controller.aspx
 
LDAP User Login: Now inside HC9.21 and later versions, if you wish to authenticate HC panel users directly from Active Directory then they will be able to do so. For more information on it, you can consult with the instructions as mentioned in the kb article given below:
http://portal.hostingcontroller.com/kb/a274/how-to-configure-ldap-authentication-for-control-panel-user-login.aspx