Can I buy a high-speed rail ticket directly at Bengbu South Station or go to Bengbu Station to buy a ticket and take a bus at the South Station?

You can buy it directly at the South Railway Station, at the window, or directly at the ticket vending machine with the second-generation ID card (just north of the waiting room).

You can also buy tickets directly online. If you take the Beijing-Shanghai line, you can enter the station without brushing the second-generation ID card (of course, you can exchange tickets at the window with the second-generation ID card or brush the second-generation ID card at the ticket vending machine to automatically issue tickets).