How to use this plugin with do_shortcode?

I hope there is a more elegant way, but at the moment I just added the following code to pass the AMP validation:

echo str_replace('<form action="http:', '<form action-xhr="', do_shortcode('[contact-form-7 id="9"'));

And in functions.php of my AMP theme:

function my_amp_post_template_head() {
	echo '<script async custom-template="amp-mustache" src="https://cdn.ampproject.org/v0/amp-mustache-0.1.js"></script>';
}

add_action('amp_post_template_head', 'my_amp_post_template_head');