ah, nevermind….
I finally got it right
add_action( 'woocommerce_thankyou', 'wc_checkout_add_order_pickup_time');
function wc_checkout_add_order_pickup_time($order_id) {
// Get the order from the id & the info we need
$order = wc_get_order($order_id);
$pickup_time = date_i18n( date( "H:i", $order->get_meta( '_local_pickup_time_select', true) ) );
echo '<h2>' . __( 'Pickup Time', 'woocommerce-local-pickup-time' ) . '</h2> <span class="wc_thankyou_pickup_time">' . $pickup_time . '</span>';
}