I have encountered this as well...I think the problem is coming from importing arcpy first. You need to import arcinfo first, otherwise you will start an instance of whatever license you are normally consuming. Try doing this:
import arcinfo
# Import arcpy module
import arcpy
from arcpy import env
import os
# Overwrite pre-existing files
arcpy.env.overwriteOutput = True
Input = "C:\\GIS_DATA\\FGDB.gdb\\InputPolygons"
Input_Layer = "Feature_Layer"
Output = "C:\\GIS_DATA\\FGDB.gdb\\OutputPoints"
try:
arcpy.MakeFeatureLayer_management(Input, Input_Layer, "", "", "field alias VISIBLE NONE")
arcpy.FeatureToPoint_management(Input_Layer, Output, "CENTROID")
except:
print arcpy.GetMessages()
Attempting to change the software class to Professional after importing arcpy will not work because importing arcpy is setting your class key to the current version. Also, you should not need to check out a spatial analyst license for this.I liked your changing the os environment variable so I tested to make sure this also works:
import os
os.environ['ESRI_SOFTWARE_CLASS']='Professional'
import arcpy
print arcpy.ProductInfo()
Just make sure to import arcinfo or set the os environment to professional before importing arcpy.