Gas prices should be rounded to the nearest penny. Nearly every day the prices change and every time the price goes up (or down) in increments of a penny. If that's the case then let it be a whole penny every time, not 9/10.
The 9/10 cents was always a method to make the price look deceptively lower. These days the consumer does not look at the 9/10 cents when determining the gas price, it is ignored because ALL the gas stations have it.
All the 9/10 cents does now is make it more difficult to make sure the pump is charging you correctly.
If McDonald's could change their value items from 99 cents to $1, I'm sure the gas companies can change as well.