If he is omnipotent, then yes, but chooses not to. Religious people often say the moral calculus of God can work in ways above or beyond our understanding, but is ultimately just. There is always a higher-level explanation; i.e. "there is evil in the world, because God wants us to have free will."
I figured God could only be Good in spite of anything He finds Himself doing over knowing the outcome of all possible choices. Through knowing everything, He would always pick that which is the most desirable towards His own aims and goals, so in the sense of Him knowing all outcomes before they happen it could only be taken as 'Just' by those tethered to fate in ways He is not.
Figuring the ability to see the future into His actions while also seeing all of space would have to have Him judged by a different metric.