Across:
8 Surprise (COR-) broadcast (-ON-) and article (-A) (CORONA) seen in The Sun? (CORONA),
9 Organisation (United Nations = UN-) with old (-O-) pair of writers (pen + ed = - PENED) (UNOPENED) is not exposed (UNOPENED),
10 Another way of saying 9 across (another way of saying ‘unopened’ = SHUT) is to close (SHUT),
11 A mince (a mince = EMANCI-) pie (= anagram indicator) and liver spread (paté = -PATE) (EMANCIPATE) and it’s free (EMANCIPATE),
12 Supports (BRACES) prop (prop/support = BRACE-) for first scrum (first ‘scrum’ = -S) (BRACES),
14 Local hooligan (yob) loses the head (y) (‘yob’ without ‘y’ = OB-) with one of those in court (-SERVER on tennis court) (OBSERVER) – presumably, it’s the witness? (OBSERVER),
15 American condition where one can’t see ahead (US NEARSIGHTEDNESS = short-sightedness) – this limits one’s outlook perhaps (NEARSIGHTEDNESS see things that are close limiting one’s outlook),
18 Someone who knows the shape of things to come (SCULPTOR) makes an impression on one of The Stones (SCULPTOR),
20 For historical types (EVENTS) there’s no harm in harvestmen (no “harm” in “harvestmen” = vesten = EVENTS),
22 Mark (mark = APOSTROPHE) indicates some of the letters are missing (APOSTROPHE),
24 Partnership (TEAM) to curate a museum’s content (‘curate a museums’ content = TEAM),
25 Confusing (= anagram indicator) real duty (real duty = ADULTERY) is not for the faithful (ADULTERY),
26 Genius (TALENT) old Roman capital? (old Roman capital/money coin = TALENT).
Down:
1 14 down (‘other’ = -OTHER) followed (= positional indicator) the start of Bubonic (start of ‘Bubonic’ = B-) (BOTHER) Plague (plague/nuisance = BOTHER),
2 Rank (SORT) of Marshal? (marshal/put in order = SORT),
3 Travel overseas (WATER SKI) to drink (WATER) with endless (end “less” = S-) members of the family (kin) briefly (n) (“kin” without “n” = -KI) (WATER SKI),
4 The ambiance (AURA) in some restaurants (in some ‘restaurants’ = AURA),
5 Twists someone’s arm (FORCES) to produce (= anagram indicator) fresco (fresco = FORCES),
6 Hasn’t got the bottle (TEMPERANCE) or the self-control? (TEMPERANCE),
7 Too wound up (RESTLESS) to relax (REST-) on the foreign (the = -LE-) ship (-SS) (RESTLESS),
13 Yells scare (yells scare = CARELESSLY) criminal (= anagram indicator) in a reckless way (CARELESSLY),
14 What’s the alternative (OTHER) to removing mess from rest homes? (removing ‘mess’ from ‘rest homes’ = retho = OTHER),
16 Get away (escape = ESCAP- E) from Bill (-AD-) inside (ESCAPADE) fooling around (ESCAPADE),
17 I (“I” = EYE) heard (= homophone indicator) this is used by swingers (TEE-) going to the (the) limit (e) (‘the’ without ‘e’ = -TH) (EYE TEETH) and they’ve a real bite about them (EYE TEETH),
19 Mark (mark = TARGET) immersed in Gibraltar getaway (immersed in’ Gibraltar getaway’ = TARGET),
21 Glad to leave Stalingrad (‘glad’ to leave ‘Stalingrad’ = stinra = TRAINS) in coaches (TRAINS),
23 Settles the bill (PAYS) for both sides at parting of the ways (both sides at ‘parting of the ways’ = PAYS),
24 Extract from support literature (extract from ‘support literature’ = tlit) raises (= reversal indicator) (tlit = TILT) one of the tips (TILT).