No, but if you want Moksha, it's the only way possible.
Jnana yoga, bhakti yoga, karma yoga, raja yoga. Mutually complementary, for sure.
Devotion towards a personal deity is certainly not necessary, although perhaps devotion in some sense is. It emerges naturally as one follows one's path.
I am of the belief that the Buddha, and many of his followers, attained moksha, and that when Buddhists today talk of enlightenment it is the same as in Hinduism.