Extending CRED allowed tags

add_filter( 'wp_kses_allowed_html', 'esw_author_cap_filter',1,1 );

function esw_author_cap_filter( $allowedposttags ) {

//Here put your conditions, depending your context

if ( !current_user_can( 'publish_posts' ) )
return $allowedposttags;

// Here add tags and attributes you want to allow

$allowedposttags['iframe']=array(

'align' => true,
'width' => true,
'height' => true,
'frameborder' => true,
'name' => true,
'src' => true,
'id' => true,
'class' => true,
'style' => true,
'scrolling' => true,
'marginwidth' => true,
'marginheight' => true,
);
return $allowedposttags;
}