In 709 AD, in the Iron Age, a spacecraft crashes in the Viking kingdom of Herot, Norway, and the pilot Kainan survives. He turns the beacon on; learns the language and culture of the planet using a machine; and finds that the predator, Moorwen, that he was transporting, had escaped. While chasing the alien monster, he finds a village completely destroyed and is arrested by the warrior Wulfric, believing that he killed the locals - Kainan is brought to Herot as a prisoner.
From this page, the details you mentioned:
Kainan's people came to the Moorwens' world to establish a colony, killing the natives and claiming the planet for themselves. As a reward, Kainan's wife and son were given a home in the new colony, while Kainan and the armed forces left for other conquests. Later, one surviving Moorwen slaughters all the colonists, including Kainan's family. Kainan was dispatched to capture the beast and was returning with it to his homeworld when it broke free and caused the crash.
Most of what you've described takes place in flashbacks, but otherwise it's a perfect fit.
You can browse through many more screenshots here.
Read more about the movie here, here, here and here. Watch the trailer here or here.