Hi,
The issue in this case is not related to the search plugin. As I can see, you are trying to display a pop-up within the results page via custom code. You are invoking the:
[php][sg_popup id=9][/php]
..shortcode there. That popup should contain this form shortcode, as I can see in the editor: https://i.imgur.com/uXxBSAz.png
However that shortcode is either not initialized when the pop-up shortcode is exectuted, or does not exist. Some plugins require a valid Post object to work properly. The issue is not that the pop-up content is not visible, but that the cred_form shortcode returns an empty content on that page, thus is probably not initialized.
