。
History class starts at 9.
Literal
History [of-の] class [topic-は] 9-o'clock [at-に] starts.
A minimal schedule statement. 歴史の授業 is a standard N+の+N construction for subject-matter modification. 始まります is the polite form of 始まる (intransitive 'to begin'), paired with its transitive counterpart 始める ('to begin something').