Opinion:
Average life of an OPE battery is about 3 years (or so).
Average life of a starter might be about 10 to 15 years or more and of course would depend on too many factors to really be able to give a "reliable average life span".
But, the "it takes 2 or more turns of the key before the starter operates" statement does hint at battery standing voltage being down just a bit from the desired 13.2 voltage that indicates a "fully charged" battery.
That statement might also be an indication of poor contact (perhaps due to corrosion) in some switches that make up the solenoid control circuit.

There are some specific tests you can do to help determine if you have a problem in switches, but before we go to a lot of testing for that, I think that a 9 year old battery should be load tested before doing anything else.
Take the battery to a parts house or a shop and have a bona fide load test done.
Whatever that shows should determine where we go from there.
"still holds a charge" is much too ambiguous a statement to use in diagnosis.

IF it starts "without a problem" on subsequent tries, the battery, starter motor etc. is obviously good.

I'd look for a "flaky" key switch or clutch/brake switch.

Mownie & Bill, thanks for your advice.

The battery ground cable connection to the frame is an oft overlooked possibility. The mounting surfaces should be bright, clean. Symptoms do suggest possibility of poor connections somewhere.

A similar problem like to drove me up the wall a year ago. Turned out a previous owner had attempted to splice the battery cable, the splice being in an invisible place, the solder job was bad and cable mating ends were corroded.

Walt Conner