Tubedoku

Tubedoku for those who dont know is a daily puzzlewhere you guess the station for a number of questions -think "No Northbound Platform × District Line.

Ive been a daily player for a 3 or 4 years, but I do have one thought that keeps coming back.

Given there are 21 lines across the TfL system is it possible to have all 21 lines used acoss the 9 answers if the right questions were asked?