SPACI score report for 3n9g in ASTRAL 2.04:

PDB Entry: 3n9g
SPACI score: 0.68
AEROSPACI score: 0.68

Experiment type: XRAY
Resolution: 1.43
R-factor: 0.168
PCK1 PROCHECK Ramachandran: 1
PCK2 PROCHECK Chi-1 angle: 1
PCK3 PROCHECK H-bonds: 2
WCK1 WHAT_CHECK Packing: -0.964
WCK2 WHAT_CHECK Ramachandran: 0.603
WCK3 WHAT_CHECK Chi angles: -0.147
WCK4 WHAT_CHECK Backbone: 1.04

Note: Here are links to pages about PROCHECK and WHAT_CHECK.

Here is the full WHAT_CHECK report on this protein (linked from the WHAT_CHECK site).