Two motorized 24-hour [light timers](https://en.wikipedia.org/wiki/Time_switch) are [daisy chained](https://en.wikipedia.org/wiki/Daisy_chain_%28electrical_engineering%29) between a power outlet and a light bulb. For these timers, devise schedules and choose initial times that produce the following 9-hour lighting pattern, with the largest possible whole number $d$, beginning when the outlet's power is switched on:

$~~~$ On for $\:d~$ hours,$~$ off for $\,9\,$–$\:d~~$ hours,
$~~~~$ on for $\:d~$ hours,$~$ off for $\,9\,$–$\:d~~$ hours,
$~~~~$ on for $\:d~$ hours,$~$ off for $\,9\,$–$\:d~~$ hours,
$~~~~~~\vdots$

If you are unfamiliar with these timers

Each timer repeatedly cycles through its schedule of 24 intervals that last an hour apiece.
•$~$ A circular dial determines the current point in the schedule
•$~$ A motor rotates the dial to advance through its schedule whenever power is supplied to the timer
•$~$ You may initially set the dial to any minute of any interval
•$~$ You may preset each interval to ON or OFF
•$~$ When the dial is in an interval that was set to ON, the timer becomes a direct connection for power to flow to whatever is plugged into the timer
•$~$ When the dial is in an interval that was set to OFF, the timer does not provide a connection between what is plugged into it and what it plugs into

The first timer is plugged into the outlet.
•$~$ It runs nonstop after the outlet is switched on
•$~$ It supplies power—but only when its dial is in an ON interval—to the second timer

The second timer has the light bulb plugged into it.
•$~$ It advances through its schedule only when the first timer supplies power
•$~$ It lights the bulb, but only while powered by the first timer and when its dial is in an ON interval.

(Related puzzle: Halve time with two timers)