I have the persuation at 9...
That sounds like a mix-up. Do you perhaps have Charisma at 9?
To bluff your way past Lukan, you need (as YnK says) to invest one point in Persuasion, which you can do at any time.*
If you've done that, then as soon as you first talk with Lukan, there will be an option that says, "Perhaps I can persuade you otherwise." If you see that, then it's just a matter of making the right dialog choices. Again, as YnK says, in general go with the least specific option and let Lukan draw his own (wrong) conclusions.
If you don't see that dialog option, then check again to make sure that you actually did put that point in Persuasion.
And if by chance you've run out of CPs (character points) and you've already done the quests in town, you can exit Shrouded Hills to the west and wander or sleep in the wilderness until you've had enough random encounters to bump you up another level.
That covers everything I can think of. Good luck, and let us know how it turns out.
*Unless your CH (charisma) is below 6, which is possible with certain backgrounds such as Beat With an Ugly Stick. If that's the case, you'll have to also invest enough points into CH to bring it up to 6.