To what level can be said that Buddha 'followed' the dzogchen?

The Dzogchen-tradition first appeared in the first half of the 9th century. According to tradition, the Dzogchen teachings were brought to Tibet by Padmasambhava in the late 8th and early 9th centuries. Dzogchen is the understanding that enlightemeht cann't be found outside a person, but is immediatally present in a persons mind and consciensness. When I read it like that it seems te me that Buddha was actionally a Dzogchen (avant la lettre). But if so (i'm not sure) why is there a different separate tradition born?