Why is my exclude categories script not working?

This has only happened since upgrading to 3.5 – but it is possible that it may have stopped working – however, I’m inclined to think it’s only happened since the upgrade.

I have my index.php file below, which excludes all posts from categories 9-14 from being displayed on the blog page – unless they’ve been marked in cat 15 as well, which would then override this rule and show them on the blog page.

However – this script is now showing ALL my blog posts on the blog home page – can you see what’s wrong with it?

<?php get_header(); ?>

<article class="main">
<?php if ( have_posts() ): ?>

<?php
$paged = (get_query_var('paged')) ? get_query_var('paged') : 1;

query_posts('posts_per_page=6&paged=' . $paged);
?>

  <?php get_sidebar(); ?>
    <div class="blogIndex">
      <h2>Latest Posts</h2>	

<?php while ( have_posts() ) : the_post(); ?>

<?php if( in_category('9,10,11,12,13,14') && !in_category('15') ) continue; //if it's category 9 or 11, but not in 15, continue
 ?>
      <article>
          <a href="<?php the_permalink(); ?>"><?php the_post_thumbnail(); ?></a>
          <h2><a href="<?php esc_url( the_permalink() ); ?>" title="Click to view: <?php the_title(); ?>" rel="bookmark"><?php the_title(); ?></a></h2>
          <!--time datetime="<?php the_time( 'Y-m-d' ); ?>" pubdate><?php the_date(); ?><?php //the_time(); ?></time-->
          <?php the_excerpt(); ?>
          <p class="button"><a href="<?php the_permalink(); ?>">read full post</a></p>
        </article>

    <?php 

/*      $i++;
      if ($i % 3) {
      // odd number
      } else {
      echo '<hr>';
      }
*/
    endwhile; ?>
  <?php if (  $wp_query->max_num_pages > 1 ) : ?>
          <div class="prevNext">
            <p class="nextPostsLink"><?php next_posts_link( __( '&larr; Older posts', 'twentyten' ) ); ?></p>
            <p class="previousPostsLink"><?php previous_posts_link( __( 'Newer posts &rarr;', 'twentyten' ) ); ?></p>
          </div>
  <?php endif; ?>
    </div> 

    <?php else: ?>
    <h2>No posts to display</h2>
    <?php endif; ?>

</article>

<?php get_footer(); ?>