If that is the case, and BIL B is removing the land from you and asking that you till it...........

but you're keeping land owned by BIL A.........

I would till it..........just so BIL B cannot cause discomfort for BIL A.

Would not make any difference to me if BIL   A said that he didn't like his BIL, and therefore if you didn't till it he would not give a rat's rear...........I would still do it, just so the SISTER who links the two cannot say a nasty thing about you, and cause discomfort for BIL  A........the "good guy".

Don't care how you cut it, or how many times people verbalize something---------getting into the potential middle of a family problem is a problem to be avoided.

If you were talking about 209 acres.........as compared to 9...........different story, since the financial side would materially sizeable........but 9 acres............not worth the downside.

Do what you need to do to keep BIL   A   comfortable........and that means keeping his sister happy.........or his wife, however the linkage is........

You cannot be there to defend yourself when the nasty comments are made behind closed doors...........regardless of whether you are right or wrong in your position.