Latin Square - solution

Below the break is the solution and notes for Latin Square.

The letters of the word LATIN form the central Latin square.

Clues

Across (letters from the Latin square underlined)

1 Subsidiary company funds low-ranking tennis player (9, two words) PETTY CASH
PETTY + [Pat] CASH

8 Endearing short wild girl (8) ADRIENNE
anagram of ENDEARIN[g]

10 Sample of granular material brought back from the moon (5) LUNAR
backwards in 'gRANULar'

11 Likely to be flexible but powerless (6) LIABLE
PLIABLE less P (power)

12 City borders destroyed in workers' protest (4) OSLO
[g]O-SLO[w]

13 Somewhat devious? I'm only a man! (5) SIMON
hidden in 'deviouS I'M ONly'

14 Being biased is no good (8) SLANTING
'S (is) + NG (no good)

15 Ruddy long track! (8) RUTILANT
RUT (long track)

16 Check earth and air (9) VENTILATE
VET + E

18 Carlos regularly leaves from America (8) CILANTRO
C[a]R[l]O[s]

20 Barely cutting down not a thing (8) SCANTILY
SCYTHING less THING

22 Press obsession? (5) CRUSH
two definitions

25 Opening act which introduces an alternative (4) DOOR
DO (act) + OR

27 Astrology's bull! (6) TAURUS

28 Nil-nil, and players' captain's extremely lazily going round in circles (5) LOOPY
O-O (nil-nil) + P (players' captain) all in L[azil]Y

29 Exemplary driver starts to brake legendarily early (8) LAUDABLE
[Niki] LAUDA + B[rake] L[egendarily] E[arly]

30 Remembering about temporary accommodation: it carries a charge (9) RETENTION
RE + TENT + ION

Down

1 Place for genteel games — average score for us around 50 (7) PARLOUR

PAR + OUR around L (50)

2 Second half of manufacturing-related test (5) TRIAL

second half of INDUSTRIAL

3 Vine from Amazon embedded in tweet I'm bookmarking (5) TIMBO

hidden in 'tweeT I'M BOokmarking'

4 Screams "absolutely!" if playing with 23 (5) YELLS

anagram of ABSOLUTELY (with 23dn U-BOAT)

5 Year written in roman numerals? (5) ANNUM

hidden in 'romAN NUMerals'

6 It might be festive to add spices (6) SEASON

two definitions

7 Ran into Tory MP giving pompously aggressive speech (8) HARANGUE

RAN in [WIlliam] HAGUE

9 In question, but not answer paper (6) TISSUE

AT ISSUE less A (answer)

16 Very casual working, getting starter of risotto and carrying liquid around (8) VASCULAR

V + anagram of CASUAL + R[isotto]

17 Sample something unknown in fish? (6, two words) TRY OUT

Y in TROUT

19 Moaners get angry and they row (7) OARSMEN

anagram of MOANERS

21 Nothing left in Native American language (6) CREOLE

O (nothing) + L (left) in CREE

23 European craft beer's head has hint of unusual grain about it (5) U-BOAT

B[eer] in U[nusual] OAT

24 He scored kids' game, missing second half reportedly (5) HAYDN

sounds like "hide and" from "hide and seek"

25 School short of two euro coin (5) DUCAT

EDUCATE without two Es

26 Small antelope, or short wading bird (5) ORIBI

OR + IBI[s]

Notes

A search on Quinapalus' excellent Qat tool delivered a list of words containing jumbles of LATIN, then a brief programming exercise found a way of arranging five of these so that no column contained the same letter twice. Fortunately a filled grid was possible from this starting point without too many obscure words. I had hoped to have no unchecked letters in the across answers involved in the square, but in the end had to leave two uncrossed; though perhaps this made working out the arrangement of the square a little less easy for the solver.