Across
'Shock and awe' upset rogue dissenting group (12)
I haven't cracked this one yet — but Fifteensquared have:
anagram/"rogue" of (upset)* + FACTION="dissenting group"
Lightning power in Blitz (5)
Viewed without subscription, just banking on film needing nothing (4-2-3)
I haven't cracked this one yet — but Fifteensquared have:
FAIR="just", around/"banking" RE=about="on" + ET=Spielberg "film" + O="nothing"
19 literature is both this and that, would you say? A shade (4,3)
Devoted king stamps a deed (7)
I haven't cracked this one yet — but Fifteensquared have:
R (Rex, "king") inside A DOING="a deed"
Beginning of rumblings in Mexico, the ground giving off heat (10)
I haven't cracked this one yet — but Fifteensquared have:
beginning of R-[umblings], in anagram/"ground" of (Mexico the)*
Old outlaw in Scottish town (4)
Immaculate as Swiss cheese, we hear? (4)
As in Nordic novel? (6,4)
I haven't cracked this one yet — but Fifteensquared have:
anagram/"novel" of (As in Nordic)*
Acceptable to rip off book by Welshman, 19 writer (2,5)
7d
Line in red and white stripes originally without success (7)
I haven't cracked this one yet — but Fifteensquared have:
L (Line), in WINES="red and white" + S-[tripes]
One has to fight criminal writing (9)
Tale ultimately penned by Nordic boy just starting primary school? (5)
I haven't cracked this one yet — but Fifteensquared have:
definition refers to the age a child might be starting primary school [perhaps specifically in Nordic countries?] ultimate letter of [Tal]-E, inside SVEN="Nordic boy"
Instil say suspicion at the outset in crime, as 19 writer (5,7)
I haven't cracked this one yet — but Fifteensquared have:
a Swedish writer of SCANDI NOIR [wiki] "Instil" becomes 'in STIL' EG=e.g.="say", put in STIL; plus S-[uspicion] in ARSON="crime"
Down
Exeter evacuated, around which wind blows up – American streets emptier? (5,4)
I haven't cracked this one yet — but Fifteensquared have:
definition: an event that might empty the streets of America if everyone goes inside to watch it on TV E-[xete]-R evacuated of its inside letters; with anagram/"wind" of (blows up)* going "around"
See 24
Certainly endless energy directed upward turned the air blue (5)
I haven't cracked this one yet — but Fifteensquared have:
definition: swore, used the F-word DEFF-[o]="Certainly" without the end letter, plus E (energy); all reversed/"directed upward"
From two continents, as Armenia possibly? (9)
I haven't cracked this one yet — but Fifteensquared have:
anagram/"possibly" of (as Armenia)*
8 of 19? Something not worth having, I should add (6)
Borders closed off in country of sultanate (5)
I haven't cracked this one yet — but Fifteensquared have:
[R]-OMANI-[a]="country" with the outer letters ("Borders") taken off
See 24
Keep puffing, Puff? (6)
Reported broken window of a clergyman (9)
Girl hugged by boy after relative recovered expenses (5,4)
I haven't cracked this one yet — but Fifteensquared have:
KEN="boy" around EVE="Girl"; after BRO=brother="relative"
Olympian gold finally given to noisy crude American (8)
I haven't cracked this one yet — but Fifteensquared have:
definition: a god in Greek myth – Olympian as in having a place on Mount Olympus [gol]-D, plus anagram/"crude" of (noisy)*, plus US="American"
'Hello sailor' appropriate? (6)
Insurrection is curbed by cartel (6)
Lover's wife, Greek character important, by the sound of it? (6)
I haven't cracked this one yet — but Fifteensquared have:
reference to the story of Psyche as the wife of Cupid ("Lover") [wiki] sounds like 'psi + key'="Greek [alphabet] character + important"
Group: into eighteen one twice goes! (5)
Now forgotten, true maverick comes into range with 19 (5,5,3,6)
Type letters or click words in the clue