There is a serious tension between (1) an all-knowing God, and (2) human free will. The basic idea here is that God already knows what we're going to do in the future. And if God knows that, then our actions are such that we couldn't have done otherwise. If this is what we're talking about with free will, then God's omniscience is, in fact, incompatible with free will.
But the story is much more complicated than this.
As a quick aside, I watched the video you linked to, lozerfac3. R. C. Sproul (the lecturer) is a Calvinist, and he's having to jump through some major hoops because of that. Calvinists believe in predestination, so he's trying to work that bit into a coherent notion of free will. His understanding of the notion of free will, however, is very weak. This is partly because he is a theologian and not a philosopher. So he ends up conflating metaphysical worries with ethical ones. His view is also deeply inconsistent. It's close to a Humean view (i.e. David Hume) notion of free will, but he ends up making a move to talk about self-determination. This is both a misunderstanding of what determinism is, and something that is metaphysically inconsistent.
But let me give some fairly standard moves that are given to resolve the tension between omniscience and free will.
One move is to think about what it would mean to know what someone was going to do. Let's say you have a kid, and your kid's favourite ice cream is mint chocolate chip. If you put a bowl of this ice cream out, you know your kid will eat it. And this seems compatible with free will. You know enough about your child's desires and inclinations to know how they will act in certain situations. God's omniscience allows Him to know how we would act in any circumstance, because He fully understands our nature, desires, and inclinations.
This is where a metaphysical definition of free will comes in. The Humean notion I referred to earlier says that an agent acts freely if her action comes from her desires. This is what's called a compatibilist notion of free will. It doesn't deny determinism--the claim that all events are caused. My desires are caused by lots of different things: biology, brain chemistry, personal history and memories, etc. These causes can ultimately be traced to events outside of me and my control. But so long as my actions are the result of my desires or inclinations, then I have acted freely.
(This is close to what Sproul said, but not quite. He ended up using Hume's theory of action along these lines (which is why it sounds close) but then made a dubious move when talking about free agency. I'm just noting this, rather than engaging with it, because it's complicated stuff.)
So here's the upshot. If your definition of free will is that you could have done otherwise, then it looks like we lack free will. In fact, this is precisely what the incompatibilist notion of free will is (those who deny either the free will thesis or determinism). But if acting freely is something more nuanced than this, then we can get away from the worries about God's omniscience.
Think about it this way. Determinism seems to be true--every event has a cause. That much is clear. Adding God to the mix doesn't actually offer a unique challenge to free will given this. After all, God just needs to know the deterministic events that led up to a particular choice. Those events would be in place with or without God.
With these considerations in place, the challenge now is to morally responsibility in the divine sense. There are moves we can make to rescue the notion of moral responsibility--at least as far as human-to-human interaction is concerned. But there are worries about these moves when it comes to divine responsibility. If I'm ultimately not responsible for my character or my desires, then how can I be eternally punished (or rewarded) for acts that result from those desires? On this front, I'm not aware of any strong apologetic moves that can rescue moral responsibility in the relevant sense.
