Sim, absolutamente ele usou o lado negro da Força. Temos algumas fontes para isso;
A partir da Guerra nas estrelas em 100 cenas (totalmente da Disney-canon).
Anakin searches the desert wastes for his mother. His quest ends in grief and pain, leading to rage fuelled by the dark side of the Force. The episode is a glimpse of the future: Anakin's inability to master his emotions will lead to tragedy for himself and those he loves
e de dentro da Novelização Oficial , é bastante óbvio que suas habilidades de Força estão sendo aprimoradas por sua raiva e ódio
At that time, the only meaning, the only purpose, that Anakin could fathom was that of the rage building within him, an anger at losing someone he did not wish to give up.
Some small part of him warned him not to give in to that anger, warned him that such emotions were of the dark side.
... [Anakin kills a bunch of Sandpeople using the Force and his lightsaber]
And then he was running, his strides enhanced by the Force, overcoming the fleeing creatures, slaughtering them, every one.
He didn’t feel empty any longer. He felt a surge of energy and strength beyond anything he had ever known, felt full of the Force, full of power, full of life.