Category sticky latest

What you’re looking for is best achieved using a custom query:

$top = new WP_Query( array( 
    'category' => 'YOUR_CATEGORY_SLUG',
    'orderby' => 'post_date',
    'order' => 'DESC',
    'posts_per_page' => 1 
) );

if( $top->have_posts() ) {
    $top->the_post();
    // Do things as if we were in the loop...
}

By default, sticky posts are brought to the top of any query results.