In addition to the loss of the aerodynamic nose, it also started tumbling simply because the engines were powered off. Modern rockets, falcon 9 included, are no

In addition to the loss of the aerodynamic nose, it also started tumbling simply because the engines were powered off. Modern rockets, falcon 9 included, are not actually aerodynamically stable during flight, and rely on active controls from gimballing the engines to keep pointed in the right direction. Once the engines power down, the rocket has little chance of surviving.