I agree with @Dave Liepman and @Fredob that yoga is a great way to keep flexible and balanced. Yoga is ideal for growing older gracefully with flexibility and balance. Given that you meditate, yoga should be a nice fit for you.
My favorite morning routine however, is Joseph Weisberg's 3 minute stretching routine that targets the whole body with six 30 second exercises. These target the spine, torso, hips and legs. Some of the exercises are yoga stretches like child's pose and cobra. After a quick warm up as you describe, the 3 minute stretching routine is effective and short enough to keep it up consistently. The routine is so compact that I don't have any excuses not to do it.
After squash, be sure to do some stretches while you are still warm. Static stretches after exercise can help with your flexibility. If you are interested in the 3 minute book, I'd appreciate it if you use our link 3 Minutes to a pain-free life. Thanks. It also includes specific stretches for specific problem areas.
Also, take a look at other areas of your life where you may be stiffening up. Prolonged sitting is often a culprit. If that applies to you, this q/a has some exercises specifically addressing a balance of stretching and strengthening as it relates to sitting.