Change the CreativeWork itemtype microdata - Genesis.

functions.php

<?php

// ..code removed for brevity.

add_filter( 'genesis_attr_entry', 'change_creative_work_itemtype', 15 );
/**
 * Change the CreativeWork itemtype.
 *
 * @since 1.0.0
 *
 * @param array $attributes Array of attributes for the "entry" element.
 *
 * @return array
 */
function change_creative_work_itemtype( array $attributes ) {
	if ( ! is_single() ) {
		return $attributes;
	}

	$creative_work_type = get_post_meta( get_the_ID(), 'creative_work_type', true );
	if ( is_valid_creative_work_type( $creative_work_type ) ) {
		$attributes['itemtype'] = 'http://schema.org/' . esc_attr( $creative_work_type );
	}

	return $attributes;
}

/**
 * Checks if the given metadata is a valid creative work type.
 *
 * @since 1.0.0
 *
 * @param string $creative_work_type Creative work type metadata
 *
 * @return bool
 */
function is_valid_creative_work_type( $creative_work_type ) {
	if ( ! $creative_work_type ) {
		return false;
	}

	$valid_creative_work_types = array(
		'CreativeWork', 'Book', 'Movie', 'MusicRecording', 'Recipe', 'TVSeries',
	);

	return in_array( $creative_work_type, $valid_creative_work_types );
}

markup.php

<?php
/**
 * Genesis Framework.
 *
 * WARNING: This file is part of the core Genesis Framework. DO NOT edit this file under any circumstances.
 * Please do all modifications in the form of a child theme.
 *
 * @package Genesis\Markup
 * @author  StudioPress
 * @license GPL-2.0+
 * @link    http://my.studiopress.com/themes/genesis/
 */


// code removed for brevity

add_filter( 'genesis_attr_entry', 'genesis_attributes_entry' );
/**
 * Add attributes for entry element.
 *
 * @since 2.0.0
 *
 * @param array $attributes Existing attributes for entry element.
 * @return array Amended attributes for entry element.
 */
function genesis_attributes_entry( $attributes ) {

	$attributes['class'] = join( ' ', get_post_class() );

	if ( ! is_main_query() && ! genesis_is_blog_template() ) {
		return $attributes;
	}

	$attributes['itemscope'] = true;
	$attributes['itemtype']  = 'http://schema.org/CreativeWork';

	return $attributes;

}

// code removed for brevity