The Ninth of Pettersson’s sixteen completed Symphonies is in a single movement. In this performance it lasts eighty-five minutes. There are two other accounts on YT. Both play for seventy, yet Comissiona’s tempos seem well-judged and, indeed, it is said were approved of by the composer, the music going somewhere, wherever that may be. As references, I am reminded, at times, of Nielsen’s Sixth Symphony and Shostakovich’s Fifteenth.
Symphony No.9 (1970) by Allan Pettersson (1911-80). Gothenburg SO/Sergiu Comissiona (recorded 1978).
PS: I have since found a fourth recording of Pettersson 9 with a timing similar to Comissiona’s.