More likely the gauge is measuring atmospheres @ 14.7 psi per. So readings between 8.2 and 9 is 120.5 - 132.3 psi. Nice thing about a gauge graduated in atmospheres is that it is neutral to English versus Metric . . .

By the way if the gauge were metric the numbers would have been really attention getting 810 - 912 kPa since one atmosphere equals 101+ kilo-Pascals
Pressure Units

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