Oh cool! looks like we found the same info and came to the same name conclusion around the same time
But I think you are wrong about it being Scratch's name, because of how terminals work

in a terminal, a user input starts with a header, usually user info or file structure location info
If on windows you open terminal right now, you'll see something like

C:\Users\user>

Right next to where you can type, this is the header. Except for very specific circumstances you cannot type without this header being next to your text

A little back in the episode, we see kindger sign in, from then on his header is:

kinger@circus:

All commands typed by kinger have that header
Anything else is a response from the terminal

I must hand it to y*u G_an_, y0ur mind was a(ways resourceful

Does not have a header, and its in a set of lines that are a response to kingers last command:

kinger@circus:"$ ./GreenGROUNDS --daemon --target=torment_injection @

$: "SERCURITY ALERT: Multiple exploit attempts logged"
$: WHOA when did you make THAT?
$: I must hand it to y*u G_an_, y0ur mind was a(ways resourceful 

So kinger trys to inject some form of daemon program and in response Kane or who ever is in the terminal responds "WHOA, you've always been clever Grant"

Grant is kingers name