The Salt Lake Tribune (Steve Luhm) reports: Among the 30 NBA arenas, Energy Solutions is the the ninth-oldest.    Of the eight arenas that are older, three have been renovated in recent years and one - Amway Arena in Orlando - will be vacated in 2010-11 when the Magic move into a new $480 million home.    There is some good news for the Jazz and their fans, however. According to team president Randy Rigby, EnergySolutions Arena has not outlived its usefulness.    “We are in an older building, there’s no question about that,” Rigby said. “But the positive thing is, we have the structure and design in place that gives us a lot of opportunities to make modifications and extend the life of this building - easily - for another 15 years. . . . It can be a very viable and productive building for a long time.”