Does Hermione Granger have bucked teeth?

No, Hermione Granger had very large front teeth until she was fifteen. She tried to convince her parents to let her shrink them but, being dentists she was not allowed.

She eventually got them shrunk when in her fourth year, when she was fifteen*, Draco Malfoy cursed her (although he was aiming for Harry) and made her teeth grow very large. When Madam Pomfrey was shrinking them she let her carry on for a little longer.

*Hermione was born on the 19th September 1979 which meant she turned fifteen just after starting her fourth year unlike Harry Potter and Ron Weasley who were still fourteen.