Obtaining timing score of a implementation run with a PlanAhead TCL script
Seems that the only way to obtain the Timing Score is reading directly the PAR report.

Next the code posted by Avrum in that old conversation at Xilinx forum

set d [get_property DIRECTORY [get_runs impl_1]]
set f [glob $d/*routed.par]
set chan [open $f]
while {[gets $chan line] &gt;= 0} {
  # puts $line
  if {[string match "Timing Score*" $line]} {set score [lindex $line 2] }
}
close $chan
puts "Timing Score is $score"


I have test it, and works fine.

Best regards