LTC3115-1 questions on layout, bypassing

Hello, 

A couple of questions about the LTC3115-1, after noting that oscillations occur on either side of the switch depending on buck vs. boost mode: 

  1. Is this the reason that Layout recommendation is to put GND plane below and around the inductor – as to minimize the coupling between Cbst1 and Cbst2? Or this GND measure is purely for EMI? What will happen if there is no GND right under the inductor (layer 2)?
  2. Can the cap on the Vout be connected directly to pins 4 and 5? (Kelvin back to GND)? 

Thank you for your help.