High pass RL circuit angular frequency
Despite the TF being zero at 0 Hz there is still a phase angle. At 0 Hz, the current taken from the input is wholly determined by R. This is because XL, at 0 Hz, is 0 ohms. Hence the current taken from the input is Vin/R. In other words, the current through the resistor and the inductor is in phase with the input voltage.

In an inductor, the voltage leads the current by 90 degrees hence, despite the voltage being zero at 0 Hz, there is a leading phase angle of 90 degrees. If you plotted a graph for phase angle versus frequency, as frequency got lower and lower you would see the output voltage tending to have a leading 90 degrees phase angle relative to the input voltage.

If you go to this site you can model an RL high-pass filter to confirm your findings. The picture below is for 1 ohm and 1 henry: -