query_posts('post_in'=>get_option('sticky_posts')) can not work

Please try without 'ignore_sticky_posts'=>1 or take a detailed look at: https://codex.www.ads-software.com/Sticky_Posts

<?php query_posts(array('post_in'=>get_option('sticky_posts'), 'showposts'=>7,'orderby'=>rand));?>

If you want to display the sticky posts,you should use ‘posts_per_page’=>1,’iggnore_sticky_posts’=>1,’post_in’=>get_option(‘sticky_posts’) .
The most important is that you don’t forget add if($sticky[0]),and delete while(have_posts()):the_post();

'post__in' has a double underline;

https://codex.www.ads-software.com/Class_Reference/WP_Query#Post_.26_Page_Parameters