The attribute growth rate of an Emperor-grade Source Beast is basically 200 points per level, which means the attributes of a level 10 Emperor-grade Source Beast will be around 2000 points of "Origin Cosmic Power", 2000 points of Attack Amplification, and 2000 points of Defense Amplification.
With Chen Mo's current attributes, though he's still a bit behind compared to an Emperor-grade Source Beast, he's already equipped to fight.
Plus, Chen Mo has an outer incarnation with equal strength to himself, making him even less apprehensive.
Sun Wu also considered the combat prowess of Chen Mo's outer incarnation, which is why he figured directly summoning an Emperor-grade Source Beast should be fine.
Even if his combat power isn't very high, Chen Mo's coordination with his outer incarnation's combat strength should be enough to handle it.
