There is a reason why frequency of services are suggested based off mileage and time.
Think of the time being the minimum required service intervals. So every year you should service the car, regardless of mileage. If you do <9k miles then this remains unchanged, but over that you have to do extra. Not the other way round.
Can you get away with servicing less frequently if your mileage is very low - yes, Should you - no. However, with a bit of common sense, you can decide what can be let slip.
E.g. An air filter won't really degrade if you aren't driving the car, but oil will, regardless of mileage.