Hello solvers! Thanks for giving this puzzle a shot. I'm not a good judge, but I think this may prove tricky. Hope you found it enjoyable? Let me know how you got on in the comments. And like and subscribe for more, obvs.
Here's the wash-up:
ACROSS. 1A1AExceptions returned by bash (4)[----]. Reversal of "exceptions" = BUTS. The surface reading is meant to be Linux-related. 4A4AOx, perhaps not so exalted (5)[-----]. Double definition. 7A7AHomer's not half a messy eater (3)[---]. Subtract half of "Homer" = PIGEON. 8A8APenny once more drops one - it's hardly Christian (5)[-----]. "Penny" = P + subtraction of "one" = I from "once more" = AGAIN. 9A9AArsenal censors 'Trumpist' slogan in fan press (4)[----]. Subtraction of "Trumpist slogan" = MAGA from "Arsenal" = MAGAZINE.
DOWN. 1D1DMake a mess of bob cut (4) [----]. "Bob" = S + "cut" = LOP. Apologies for this bit of pre-decimal coinage trivia. 2D2DTo fire up crystal... (5)[-----]. TO given literally + "fire" = ZAP reversed ("up"). 3D3D...started to ask, then starts to ask not (5)[-----]. "ask" = BEG + initial letters from "ask not". 5D5DArticle of concealment sported by WWI generals (3)[---]. Hidden ("sported by") in "wWIGenerals". 6D6DPen Edda's first character (4)[----]. "Pen" = RUN (as in e.g. "chicken run") + first letter of "Edda".