wmig

This simple plugin will hide posts from children categories.
It just override include_children property for hierarchical taxonomies.

Exclude Children

This simple plugin will hide posts from children categories

rmasfer

Custom Cat plugin will helps to assign taxonomies terms easier than before. You will no longer need to scroll through list of taxonomy terms.
<ul>
<li>A searchable list for assigning terms(e.g. Categories).</li>
<li>Create new terms(e.g. Categories) if no results found.</li>
<li>Supports any type taxonomies.</li>
<li>Hide default Category meta box</li>
<li>Allow only one taxonomy term</li>
</ul>

Exclude Children vs Custom Cat