Can I configure the number of recommendations displayed?

Yes, absolutely, you can choose the number of recommendations displayed in the widget. 

It can be configured using the Number of recommendations setting from the Recommendation Tuning section on the preferences page

Please note that this number does not include the current item so if you configure 2 recommendations there will be 3 products displayed (the 2 recommendations plus the current product).

Note that this setting changes the widget layout. The default value of 2 is good enough in most cases.