MINOR: Add 3.9.1 blog post (#688)

Add 3.9.1 blog post

Author: frankvicky

blog.html

@@ -22,6 +22,19 @@
         <!--#include virtual="includes/_nav.htm" -->
         <div class="right">
             <h1 class="content-title">Blog</h1>
+            <article>
+                <h2 class="bullet">
+                    <a id="apache_kafka_391_release_announcement"></a>
+                    <a href="#apache_kafka_391_release_announcement">Apache Kafka 3.9.1 Release Announcement</a>
+                </h2>
+                20 May 2025 - Luke Chen (<a href="https://twitter.com/showuon1">@showuon1</a>), TengYao Chi (<a href="https://twitter.com/zephyrankvicky">@zephyrankvicky</a>)
+                <p>We are proud to announce the release of Apache Kafka 3.9.1. This bug-fix release has several fixes, and most importantly, it adds Java 23 support. For a full list of changes, be sure to check the <a href="https://downloads.apache.org/kafka/3.9.1/RELEASE_NOTES.html">release notes</a>.</p>
+                <p>See the <a href="https://kafka.apache.org/39/documentation.html#upgrade_3_9_1">Upgrading to 3.9.1 from any version 0.8.x through 3.8.x</a> section in the documentation for the list of notable changes and detailed upgrade steps.</p>
+                <h3>Summary</h3>
+                <p>This was a community effort, so thank you to everyone who contributed to this release:</br>
+                    Alieh Saeedi, Almog Gavra, Alyssa Huang, Andrew Schofield, Anna Sophie Blee-Goldman, Ayoub Omari, Azhar Ahmed, Bill Bejeck, Bruno Cadonna, Chia-Ping Tsai, Colin Patrick McCabe, Colt McNealy, David Arthur, David Jacot, Dimitar Dimitrov, Divij Vaidya, Edoardo Comar, Federico Valeri, Florian Hussonnois, Greg Harris, Guozhang Wang, Hailey Ni, Ismael Juma, Jeff Kim, Jhen-Yung Hsu, Jonah Hooper, Jorge Esteban Quilcate Otoya, Josep Prat, José Armando García Sancio, Jun Rao, Justin Lee, Justine Olshan, Kamal Chandraprakash, Ken Huang, Kirk True, Kuan-Po Tseng, Laxman Ch, Lianet Magrans, Logan Zhu, Lucas Brutschy, Luke Chen, Manikumar Reddy, Martin Sillence, Matthias J. Sax, Mickael Maison, Ming-Yen Chung, Nick Telford, nilmadhab mondal, Parker Chang, PoAn Yang, Sean Quah, Sebastien Viale, ShivsundarR, Stig Døssing, TaiJuWu, TengYao Chi, Vedarth Sharma, Ziming Deng
+                </p>
+            </article>
             <article>
                 <h2 class="bullet">
                     <a id="apache_kafka_400_release_announcement"></a>