Actually I would have to take back what I said on it being a "What If" seeing as it has no official status of being a "What If". Being a Spin-off doesn't make it non-cannon, and it doesn't contradict with anything that happened int he "cannon" events of the series.
Planet Vegeta was still destroyed, only difference from the "filler" movie was that Bardock had survived and had gone Super Saiyan and was the cause behind Freiza's initial fear of the Saiyan's and what gave legend to the Saiyans. Seeing as the "First" Super Saiyan's true identity was never actually revealed at any point throughout the series.
Vegeta mentioned suspicions about the First Super Saiyan but the picture shown was of a Golden Oozaru, even then as a Golden Oozaru Saiyan's have their tails.
So Episode of Bardock could very well be Cannon seeing as it was the Original Concept and was Directed by none other than Akira Toriyama and Created by Ooishi Naho. So with Akira Toriyama actually playing a role in it's release in a sense since he was it's Director it supports it being an actual cannon spin-off.
