You can't do this on the same contribution page (at least not without custom code). If one of the enabled processors does not support recurring contributions the option will not be available on the entire contribution page.
The solution normally used is to have two separate contribution pages.
The problem is solved by using cf-civicrm developer version from github rather than the version proposed by Wordpress.
To understand more you can see this Post : https://github.com/mecachisenros/cf-civicrm/issues/185