If you want to have sticky posts first in results when they match the search query, just add this code to your theme functions.php:
add_filter( 'relevanssi_hits_filter', 'rlv_sticky_first' );
function rlv_sticky_first( $hits ) {
$sticky = array();
$nonsticky = array();
$sticky_post_ids = get_option( 'sticky_posts' );
foreach( $hits[0] as $hit ) {
if ( in_array( $hit->ID, $sticky_post_ids ) ) {
$sticky[] = $hit;
} else {
$nonsticky[] = $hit;
}
}
$hits[0] = array_merge( $sticky, $nonsticky );
return $hits;
}