Crystal Footprint Placement
Either will work out fine.  The XTAL is a high Q BPF so it does a good job of rejecting noise in most cases.  You do want to try and limit high edge rate signals adjacent to those traces where you can, though.  The XTAL also has very low emissions so won't induce noise into your planes.  I've done it both ways and never noticed any difference in SI one way or the other.  Place it where it makes sense for the remainder of your design.