Can I exclude pages from search results?

If you use a search module, then you can choose to exclude pages in the Module settings > Content > Exceptions > Exclude Pages

But if you're referring to the default Divi search, try the bellow jQuery code in WP Admin > Divi > Theme Options > Integration > Body Code:

Code:

<script>
    jQuery(function($){
        $( ".et-search-form" ).append( '<input type="hidden" name="post_type" value="post" />' );
    });
</script>