If meta_value = ‘yes’, then add class?

The post_class filter is your friend. Just combine it with get_post_meta().

function wpse80098_filter_post_class( $classes ) {
    global $post;
    if ( 'yes' == get_post_meta( $post->ID, '_jsFeaturedPost', true ) ) {
        $classes[] = 'my-custom-css-class';
    }
    return $classes;
}
add_filter( 'post_class', 'wpse80098_filter_post_class' );

Just replace my-custom-css-class with whatever class you want to apply to the post container in question.

As noted in the comments, this implementation relies on the post_class() template tag being called properly in the post container, e.g.:

<div id="post-<?php the_ID(); ?>" <?php post_class(); ?>>

Edit

Re: this question in the comments:

Is there a way I can dynamically prepend an a tag to the posts with the featured class?

The easiest method is probably to filter the_content:

function wpse80098_filter_the_content( $content ) {
    global $post;
    if ( 'yes' == get_post_meta( $post->ID, '_jsFeaturedPost', true ) ) {
        return '<a href="http://example.com">' . $content . '</a>';
    }
    return $classes;
}
add_filter( 'the_content', 'wpse80098_filter_the_content', 99 );

Add a very high priority number, so that this filter gets applied last.