get unserialized array without using get_option()

You can use the following two inbuilt functions to do this.

1. switch_to_blog
2. get_option

You can use both in the following way to make a function out of it which would give you the option. Put the below in the functions.php file

function wpse_get_options( $blog_id = 1 ){
    switch_to_blog( $blog_id );

    $get_option = get_option( $option ); // Replace $option with the option name
    restore_current_blog(); // Switch back to the original blog

    return $get_option;
}

Now you can use the above function to fetch the options by using the function and passing the blog id/ sub site id.

$options = wpse_get_options( $blog_id );
// Replace the $blog_id with blog id of your sub sites.