The simplest way would be to use IE Conditionals.
Note: IE10 and beyond have removed support for this feature. For modern browsers the widely accepted way of conditionally displaying content for compatibility purposes is using feature detection. Modernizr is a popular library built for handling feature detection.
For example:
<!--[if IE 9]>
<script type="text/javascript">
window.location = "http://www.ie9version.com";
</script>
<![endif]-->
Examples from the conditional site:
<!--[if IE]><p>You are using Internet Explorer.</p><![endif]-->
<![if !IE]><p>You are not using Internet Explorer.</p><![endif]>
<!--[if IE 7]><p>Welcome to Internet Explorer 7!</p><![endif]-->
<!--[if !(IE 7)]><p>You are not using version 7.</p><![endif]-->
<!--[if gte IE 7]><p>You are using IE 7 or greater.</p><![endif]-->
<!--[if (IE 5)]><p>You are using IE 5 (any version).</p><![endif]-->
<!--[if (gte IE 5.5)&(lt IE 7)]><p>You are using IE 5.5 or IE 6.</p><![endif]-->
<!--[if lt IE 5.5]><p>Please upgrade your version of Internet Explorer.</p><![endif]-->
<!--[if true]>You are using an <em>uplevel</em> browser.<![endif]-->
<![if false]>You are using a <em>downlevel</em> browser.<![endif]>
<!--[if true]><![if IE 7]><p>This nested comment is displayed in IE 7.</p><![endif]><![endif]-->