Answer:
September 9 at 9pm, the following year
Step-by-step explanation:
We are given from the question above that;
=> Theo observers a star at 9:00 P.M. on September 9.
Theo will be able to see the exact star at the same position and at the exact time of night again the following year. This is because the stars move at least one degree everyday. Thus, the star will move 360 degree in a year. So, Theo will be able to see the same star by September 9 at 9pm, the following year.