Can the interdictor use targeting scramblers on itself?

Yes.

From the RRG, page 7:

A ship or squadron is always at close range and distance 1 of itself.

Its worth noting where the confusion arises from.

"Friendly ship" can be used on the ship upon which the upgrade card resides as well as rest of fleet

"Another Friendly ship" CANNOT be used on the ship upon which the upgrade card resides

Toryn Far & Home One are the ones I can think of which are "another friendly"

Howlrunner also uses the "another friendly" terminology. Shame, because she'd be perfect, otherwise.

Howlrunner also uses the "another friendly" terminology. Shame, because she'd be perfect, otherwise.

"Perfect" aside, she's "Good Enough" for her points and other strengths..