Thanks for the provided information. WPACU plugin uses ‘administrator’ role by default as the permission when defines its admin menu and checks current user permissions.
But it allows to replace ‘administrator’ with custom permission via filter. For example, code below provides access to WPACU plugin for any user with ‘manage_options’ capability:

add_filter('wpacu_access_role', 'replace_wpacu_admin_permission', 10, 1 );
function replace_wpacu_admin_permission( $cap ) {
    $cap = 'manage_options';

    return $cap;

You can add it to the functions.php file of your active theme.