I’m speculating a little here, but the 800’s and 900’s I think are subject to weight and balance restrictions when the winter weather is bad (high winds) I’m more referring to the longer hauls like SEA/KOA. I’m surprised to read in this thread that a shorter haul flight like SJC/KOA had an issue.

As a data point ASA 801 11th January SEA/KOA after encountering a two hour maintenance delay at seatac was required to stop in SJC to refuel. It was a B739 which I believe means it was a 900.

My understanding is that the Max’s are less restricted by the above problems.