'fill in time' is a correct and usable phrase in written English.
It is typically used to describe an activity done to pass the time before something else occurs or is completed. For example: "We had to fill in time until the meeting began at 12 o'clock."
It is better to finish the day early than to extend to extend breaks, or to fill in time.
Only McCulloch and mercurial guitarist Will Sergeant remain from the band's original line-up, and tonight their new songs merely fill in time between their stream of classic, chiming, immaculate post-punk confections.
The archive was notoriously slow and you had to wait ages for someone to retrieve the documents you had requested, so I just started idly looking through some other files to fill in time.
The plaintiffs say that cooperation with Land O'Lakes will help fill in time gaps in the allegations, because Sparboe claims it left the conspiracy at some point during the class period.
It will also help prevent you from feeling lost for words and saying 'um' to fill in time.
Improvising became restricted to organists noodling around hymns and fugues to fill in time at services.
I later learnt... you were filling in time before you caught a plane".
I don't know what I expected -- perhaps retired English teachers filling in time between rounds of golf.
Ali had avoided draining himself too severely in this early period, especially in the sixth and eighth, by filling in time with some highly calculated comedy.
Stoppard no doubt hung around a lot backstage as a journalist in Bristol – he would have seen actors filling in time.
Indeed, the transitory condition of elected office is, for most Alliance politicians, merely filling in time before their inevitable quango appointment.
