stesvis

This plugin allows you to choose which post categories youe site will show on your pages. Just go to settings and deselect the categories that you want to hide. 
For the homepage it will work automatically, for the other pages you have to add a shortcode into the page.

WP Filter Post Category

msng

Filters the categories of posts shown on your front page.
<h4>How to Use</h4>
<ol>
<li>After Installation, activate the plugin. Don’t worry, it does nothing when activated for the first time.</li>
<li>Go to Settings > Home Categories to setup.</li>
</ol>
* Select the working mode from Show selected categories only or Hide selected categories 
* Check the target categories. 
* Press Save Changes .

Home Categories

Allows you to choose categories on an exclusive OR inclusive basis, unlike other plugins. This makes it easy to include only one category instead of excluding all but one category.
Well-designed plugin, and still working great.



Works great for showing one category

Filters the categories of posts shown on your front page.

WP Filter Post Category vs Home Categories