A little bit clumsy. Lots of unindicated anagrams, superfluous clue text, and possible double-up between clue and definition. 24A was interesting with a double wordplay! Not sure about the definition of 14D, I feel like it should be measurers, not to mention it's one of the unindicated anagrams.

Across

1

Most recent info bad. Town so elongated unfortunately (4,4,3,4)
LATE NEWS NOT GOOD — anagram (unfortunately) of TOWN SO ELONGATED

9

Waver starts going like a snake’s tooth (4)
FANG — FAN (waver) G (first letter of going)

10

True, is in a position to be accomplished (10)
REALISABLE — REAL (true) IS, ABLE (in a position)

11

Therefore one right, earlier than expected (6)
SOONER — SO (therefore) ONE R (right)

12

Equal in 1 and is like a big bird’s beak (8)
AQUILINE — anagram (unindicated) of EQUAL IN I (1)

13

Again, shape is the first for one hoping to remove imperfections (9)
REFORMIST — REFORM (again shape) IS T (first letter of the)

15

A widespread shout of a seaman (5)
AVAST — A VAST (widespread)

17

Bob HM mixed highly explosive (1-4)
H-BOMB — anagram (mixed) of BOB HM

19

Land on which planes come down and ventilates the coming excursions (9)
AIRSTRIPS — AIRS (ventilates) TRIPS (the coming excursions)

23

Eel heart very light and tenuous (8)
ETHEREAL — anagram (very light) of EEL HEART

24

Warder returns sunburnt and naked to make another sketch (6)
REDRAW — reversal (returns) of WARDER; RED (sunburnt) RAW (naked)

26

Right sphere left the last structural designs intended to be copied (4,6)
ROLE MODELS — R (right) O (sphere) L (left) E (last letter of the), MODELS (structural designs)

27

Piece of news made a change in time (4)
ITEM — anagram (made a change) of TIME

28

He twirls outpost in the travels of a politician (7-4,4)
WHISTLE-STOP TOUR — anagram (unindicated) of HE TWIRLS OUTPOST

Down

2

Seaman unaccompanied has a mollusc (7)
ABALONE — AB (seaman) ALONE (unaccompanied)

3

Encourage but, for example, not yet departed (3,2)
EGG ON — EG (for example) GONe (most of departed)

4

Middle ear vibrators badly marred us (8)
EARDRUMS — anagram (badly) of MARRED US

5

Science on Arabs and certain beetles (7)
SCARABS — SC (science) ARABS

6

Do back unpaid bills that are disgusting (6)
ODIOUS — reversal (back) of DO, IOUS (unpaid bills)

7

Clothing left always on a part of the vehicle mover (4,5)
GEAR LEVER — GEAR (clothing) L (left) EVER (always)

8

Leading outside broadcast lets out no good sound for flat, four-sided shapes (7)
OBLONGS — first letters of Outside Broadcast Lets Out No Good Sound

14

Home terms of resistance measures (9)
OHMMETERS — anagram (unindicated) of HOME TERMS

16

Press after two directions before starting opening this strong coffee (8)
ESPRESSO — PRESS after ES (two directions), O (first letter of opening)

18

Agree to marry Beth outside? Rubbish! (7)
BETROTH — BETH outside ROT (rubbish)

20

I'll take NE steamship due to poor health (7)
ILLNESS — ILL, NE, SS (steamship)

21

Dish, Australian, from some high-up flat area (7)
PLATEAU — PLATE (dish) AU (Australian)

22

Deceive and be an ass (6)
BEFOOL — BE FOOL (an ass)

25

Five-hundred split and current of water or air (5)
DRIFT — D (five-hundred) RIFT (split)