Can I use a 9.1K ohm resistor instead of 9.31K?

In general, when you see a high precision resistor in a circuit, it’s because it’s important that the value be respected. The 9.31K resistor (U7011) is spec’d at 1% in the schematic. That means it’s measured value will be between 9.217K and 9.403K. If you look at the circuit, it is a voltage divider and the schematic says “Divider sets ACIN threshold at 13.55V “ so yes, it’s important to have the proper value.

R7912 is a 9.1K 5% resistor, which means it can measure between 8.645K and 9.555K. If you install a 9.1K resistor, you will most likely be out of spec. You could measure it directly, out of circuit, to see what the actual measurement is but even your multimeter has a margin of error. Still, if the 9.1K resistor falls within the proper range, you could use it.

The best solution is to simply buy a new one from Digikey, it costs literally 10 cents.