JMGPhila - if 99% of the people have a different opinion, it's something you should consider.

For clauses like 9.1.2, unless it's completely explicit in the text that something (such whether it's "not acceptable") is in your absolute discretion (which, in this case, it's not), a standard of "reasonableness" will be applied by any arbitrator, judge or court. Your flight or the alternative flight is changed to arrive 30 minutes later than previously scheduled? No one will give you a refund if just you think that's unacceptable.

As for 9.2.2, I fail to see where an aircraft change would trigger this clause unless the airline is unable to "operate a flight reasonably according to the schedule". Again, "reasonably" is a well established legal standard.