9.9 Mariner shift shaft removal

[13crazyhorse]

I have a 97 9.9EL mariner outboard. I'm trying to change the impeller but after removing the usual bolts the lower unit drops down a ways but I can't figure out how to get the shift shaft off. It is pinned on the top and I can't get to it. There's an access hole on the starboard side that gives me access to a square bolt but this doesn't seem to unscrew. I don't want to break anything so I'm stuck at this point. It doesn't look like I could remove it from the lower end either. Wondering if there's any way short of removing the whole power head. Thanks for any help on this.