Hi Lauren,
Welcome to the forum.
I think I had nearly all the versions of FloorPlan 3d except V9! Soon after it's release there were many reports of little problems here and there, so I decided to wait for the next version, which was excellent, as was V11. Why have you gone back to V9 if you have V11?
I do not recall any specific reports of problems with V9 as far as joining walls is concerned. All versions were a little bit of a problem on corners but much easier if you join the wall to the flat part of the wall and drag it up to the corner, or start out from the corner and draw the wall towards the corner. To draw the wall from the corner OUT would often go at an angle, so start away from the corner and draw your wall TO the corner.
Are you printing the plans on using them on-screen? If you are printing, then you should be able to set the printer to print in black ink only. I am struggling to remember what functionality was available, as it was so long ago, but I seem to recall that you can also export the plan as a DXF file, which would be black but you would need suitable software to open it. PaintShop Pro, presumably Photoshop and maybe some other image editors, would open it, as would other CAD programs. I don't recall there being a way to change the line colours of the 2D plan. In V12 -V15 this is very easy to do - you can make any line any colour you want and there is certainly no problem joining walls at corners or anywhere. Walls are probably the biggest change from earlier versions.
If you have are going to do more of this type of work, you may want to consider getting V15 (or even V12 or V14 which you could probably pick up quite cheaply now that V15 is out). They are MUCH, MUCH more functional than v11 and earlier versions. They are very similar to use, so no big learning curve, but they will NOT open versions older than V12 so would only be suitable for new projects.
I hope that was of some help.
Allan