Solution to 7D has been deliberately left unsolved and is to be answered by a non-regular/novice commenter, with proper annotation. Those who have answered earlier in the week, please give others a chance.
Open for anyone to answer, if not solved by 1 PM.
ACROSS
1 Study starts to trace ancestral lineage of canines (6) DENTAL {DEN}{Tr..e}{An...l}{Li...e}
8 Someone on a terrace is having a baby! (7) NEONATE [T]
9 Avoid draw? (4,3) WARD OFF {DRAW}* [RA]
11 About to ask loners all over the place to stand together? (5,5) CLOSE RANKS {C}{ASK+LONERS}*
12 Cut some sweet cherries (4) ETCH [T]
16 Plan is right from start to finish and logical to begin with (8) PROPOSAL {(-a)PROPOS(+a)A}{Lo...l}
18 Old Peruvian beer may be found here (5) INCAN {IN CAN} [DBE]
20 God of war essentially! (4) ARES [T] Semi&lit
21 Spooner's unreasonable standards - they could be frowned upon! (3,7) BAD MANNERS (~mad banners to bad manners)
23 Risk is great, but not absolute (7) IMPERIL IMPERIaL
24 These discriminators are on board? (7) SEXISTS {S{EXIST}S}
25 Had spent time, to take wife out (6) TASTED (+t-w)TASTED
26 Enter with extremely tipsy author around lunchtime (4,2) TYPE IN {TipsY}{PE{1}N}
DOWN
1 People get on when love is expressed (5) DWELL {Do WELL}
2 Abstainer's turned on by hot nurse (3-4) NON-USER {ON<=}{NURSE*}
3 Members of a rock band? (9) ASTEROIDS [CD/GK]
5 At last, scrub your butt cheek (5) BRASS {s..uB}{youR}{ASS}
6 Say, buffalo and bear finally teamed up (3,4) RED MEAT {beaR+TEAMED}*
7 A time to avoid pretentiousness, and care (9) A?F?C?I?N ()
15 A pill they popped for pastime (9) PHILATELY*
17 Have mixed up pesos with shillings (7) POSSESS {PESOS*}{SS}
19 Intimate clip from biopic on Fidel (7) CONFIDE [T]
21 In Bangalore on vacation, kid gets reward (5) BRIBE {Ba...rE} over {RIB}
22 I unloaded supplies in shop (3,2) RAT ON RATiON
Reference List
Sun = S, About = C, Absolute = A, Time = T, Wife = W, Hotel = H, Shilling = S