Isolated DC/DC converter help
this datasheet does not indicate any input or output filters or
  recommended capacitors for optimal operation except a 10F MLCC at the
  output , any recommendations on this ?


First of all read this section in the data sheet on how to make it compliant with EN55032: -




  I would really appreciate if someone would share his insights on
  whether an isolated DC/DC converter of a fixed output (12V) can
  sustain that output even when input is lower than 12V, the datasheet
  says the input range 9-36 VDC which may be the answer but i would
  really like to get a confirmation if possible.


Secondy, yes it will work from 9 volts input to 36 volts input because, internally, is a flyback converter.