You want to know more about the Force Safe Search feature in K9 Web Protection.
The Force Safe Search feature of K9 is enabled by default. The feature will force the use of safe (filtered) searching on the following search engines: Google, MSN/Live, Yahoo, Ask, A9, Altavista, and Orange, even if the user conducting the search has selected “Do not filter my search results” from the Google Preferences page. For information about this Google feature, please visit http://www.google.com/preferences.
Please Note: K9 Web Protection uses the safe search functionality provided by the individual search engines; this does not guarantee that all adult-oriented content will be blocked.
To enable or disable the Force Safe Search option, Launch K9 from your Start menu, click Setup, and login with your administrative password. Click Web Search Options in the left column and make sure the Force Safe Search box is checked. Remember to click Save at the bottom of the page.