Phantom power is typically used to power microphones, and a typical bass amp would not be configured to receive a microphone input, so I doubt that a bass amp would supply phantom power. However, if he is running his VT Bass DI into a preamp that also was designed to accept microphone inputs, then it would probably be able to supply phantom power, thus powering his pedal. Not sure if the VT Bass DI can be powered this way, I know that the VT Bass Deluxe can.
The reviewer might be taking phantom power from some other source (like a board) to power his pedal via xlr, and be sending the signal to his amp through a 1/4 inch regular guitar cable.
"Bass players do it standing up in the back over by the drummer"