Where is the Second serial Port on CCR1009?

RouterOS General
1 
CCR] > port print 
Flags: I - inactive 
 #   DEVICE NAME                     CHANNELS USED-BY                   BAUD-RATE
 0          serial0                         1 Serial Console            auto     
 1          serial1                         1                           auto

There is one RS232 Male interface in front of the Router but where is the second one?

2

Probably on some header on the board or not even that.
You can also often find this in other equipment. The Linux kernel auto-detects certain devices in the system chips and lists them as devices, but that does not mean the printed circuit board actually has a connection to the pins!
Depending on how the board is layed out, it may sometimes be possible to make that port accessible to the user. However, it likely would still need RS232 driver hardware.
When you want an extra serial port, a USB serial cable is probably easier.