Bump 4.9 branch to version 4.9.9.

Built from https://develop.svn.wordpress.org/branches/4.9@44078


git-svn-id: http://core.svn.wordpress.org/branches/4.9@43908 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/about.php

@@ -33,6 +33,16 @@ include( ABSPATH . 'wp-admin/admin-header.php' );
 
 		<div class="changelog point-releases">
 			<h3><?php _e( 'Maintenance and Security Releases' ); ?></h3>
+			<p>
+				<?php
+				/* translators: %s: WordPress version number */
+				printf( __( '<strong>Version %s</strong> addressed some security issues.' ), '4.9.9' );
+				?>
+				<?php
+				/* translators: %s: Codex URL */
+				printf( __( 'For more information, see <a href="%s">the release notes</a>.' ), 'https://codex.wordpress.org/Version_4.9.9' );
+				?>
+			</p>
 			<p>
 				<?php
 				printf(

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.9.9-alpha-44053';
+$wp_version = '4.9.9';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.