tracker & Dave & others,
Please take the thing apart at your earliest convenience.
There is probably only one R9S owner who had any problems, and you are looking at him.
My latest debacle was strictly caused by the owner not having enough common sense to push the pin back in, all the way, instead of flush with the left side. That's why the slide would not move afterwards.
It would help to have channel lock pliers to hold the spring assembly as you stick it back into the front of the gun.
Consider using a tapered stick to hold the slide open to align the pin with the holes. I don't remember the distance the slide is opened. Perhaps it is around 1/4 inch, or whatever.
Clear off the table, sit down and relax, and you will absolutely do a fine job.