It is HPOS compatible

Unfortunately, HPOS compatibility is not declared, but the code is compatible [by my review].

You can add code to the primary plugin file to declare compatibility if you would like:

add_action('before_woocommerce_init', function(){
    if ( class_exists( \Automattic\WooCommerce\Utilities\FeaturesUtil::class ) ) {
        \Automattic\WooCommerce\Utilities\FeaturesUtil::declare_compatibility( 'custom_order_tables', __FILE__, true );
    }
});