Derek Hough has paid tribute to “wild ball of energy” Richard Simmons. The fitness guru was found dead in his Los Angeles home over the weekend, just one day after his 76th birthday, and Derek took to Instagram to remember their first meeting in 2007, when Derek, 39, was paired with Jennie Garth on ‘Dancing With The Stars’. He wrote: “In 2007 My very 1st season on @dancingwiththestars I had the pleasure of meeting this wild ball of energy :). “Mr. Simmons was there to help @jenniegarth with her confidence but ended up boosting mine instead with a song about my ‘perfect’ hair. Rest In Peace.” R…