Sharepoint - Configuring timer jobs in sharepoint online

It's not possible to configure (change schedule, trigger, etc.) timer jobs in SharePoint Online.

The best thing you can do is to make sure your policy settings are good and wait for jobs to be completed. :)

There is a way to check when it last ran and based on that you can deduce when's next run is likely to be.

Open up the SharePoint Online site collection in SharePoint Designer 2013 and go to Site Options. The properties below are of your interest.

dlc_PolicyUpdateLastRun
dlc_ExpirationLastRun 

I've used this to test retentions policies before in SPO. In fact, when I tested couple times I figured out that for a newly created site collection, these jobs ran within 24 hours. But that was few months back.

Something is better than nothing. Good Luck.