With the premise that a 3x3 grid alignment system is going to be introduced into the game, and enforced, here is how I would start looking at it:
First, establish with the players what is essential to each coordinate. You have to be specific about what the expectations (and especially) requirements will be.
Following that, encouraging any sort of behavior tends to work best with a carrot and stick system, rather than just a stick (which is generally how alignment has worked out). If you just penalize players for "acting out of alignment" in an arbitrary way, then they will just become upset. This goes into clear expectations, above.
Create a carrot: What benefit will players get if they act in accordance with their alignment and it makes their life more difficult? In other words, what do they get if they don't take the easy way out? That is really what we're getting at here. XP is always popular with players, but some groups are opposed to differing rates of advancement. A small bonus to actions directly related with that decision, perhaps representing taking strength from your convictions.
Create a stick: What penalty will players get if they act outside of their alignment? Essentially, what happens if they take the easy way out? To follow in theme with the previous example, a small penalty to all of their actions until they come to terms with what they did. This may mean making it right in some way (perhaps even unrelated), or changing their alignment to reflect how they now view the world. In the latter case, I would strongly suggest that there is no loss of XP or other abusive penalty. People change, it doesn't make it harder to get better.
Those are some places to start, but definitely establishing clear expectations, then creating a reward and penalty to reinforce those expectations are the best way to get buy in. At least in my experience, as in all things, ymmv.