I've completed the "crosswordy" bit (solving the clues, spotting the missed letters, siting and resolving the clashes). I've even gone as far as dropping appropriate letters into the bottom row. Now I've arrived at the "colouring in" bit, I'm a bit stumped.
I'm assuming that the 9 letter word is the thing generically hinted at by the 5 words given by removed letters. In the preamble the words "cells touching at a side or corner" are used. I took "sides" to mean only the vertical dividing lines betwen cells (NOT the horizontals). However, if I'm starting from the only possible initial letter in the top row, I can only trace my required word through cells connected through their tops and bottoms (Row 2 Column 6 to Row 3 Column 6). Can someone give a hint to the highlighting? I've already seen (6 letters NE to SW) a line, and dangling from it (3 letters N to S) a thematic metal object.