I am converting creo files to Autocad in .dxf/.dwg formats but when I measure the converted creo drawing in AutoCAD I am getting those results displayed in Inches.
That's the format set in your drawing template. You should change it for future drawings. Set the path to a metric template with a config.pro setting like this:
template_drawing C:\Path\To\Drawing.drw
For your current drawings go into the drawing options search for "unit" and change it from "inch" to "mm". I haven't got access to Creo at this minute, but drawing options are probably in the File menu.