Issue echoing the site’s title in Genesis child theme

Your code indeed contains a syntax error, which is unescaped quotes:

$creds="[footer_copyright] <?php echo get_bloginfo( "name' ); ?>';   // bad - ' not escaped
$creds="[footer_copyright] <?php echo get_bloginfo( \"name\' ); ?>'; // good - ' escaped

But even if you escape the quotes, the code will not work as expected.

So to make it work as expected, use concatenation like so:

$creds="[footer_copyright] " . get_bloginfo( 'name' );