The port 9001 seems to be used by Microsoft-HTTPAPI/2.0. I get this from the browser doing a http://localhost:9001/
HTTP/1.1 404 Not Found
Content-Type: text/html; charset=us-ascii
Server: Microsoft-HTTPAPI/2.0
Date: Thu, 09 Apr 2020 08:10:11 GMT
Connection: close
Content-Length: 315
Using netstat -aonb | grep 9001:
TCP 0.0.0.0:9001 0.0.0.0:0 LISTENING 4
TCP [::]:9001 [::]:0 LISTENING 4
TCP [::1]:9001 [::1]:50916 TIME_WAIT 0
TCP [::1]:9001 [::1]:50957 TIME_WAIT 0
So PID 4 is ntoskrnl.exe.
I checked that Internet Information Service is off
How could I investigate further ? Thank you for your help
