Visiting caves and info Datong

I am arriving to Datong by train at 4:30 am and plan to visit the Yungang grottoes early morning; probably going by taxi; and in the late afternoon going to Beijing. Is it safe and ok to stay at the Datong train station from 4:30 am until 8am or 9am before going to the caves? or is it better to book a hotel for a few hours? are there lockers to leave a piece of baggage at Datong train station? What is the best way to go to beijing from Datong, a minivan? Thank you!!