No 13046, Monday 21 Sep 2020, Karaoke

Solution to 4D has been deliberately left unsolved and is to be answered only by a non-regular/novice commenter, with proper annotation. Those who have answered earlier in the week, please give others a chance.

ACROSS

9   Philosopher cooked risotto without onions originally in drink (9) ARISTOTLE {A{RISoTTO*}LE}
10 Strained future maybe (5) TENSE [DD]
11 Start boarding school after end of spring (3,2) GET ON {s...nG}{ETON}
12 Professional workshop equipment gets around 100 procedures (9) PROTOCOLS {PRO}{TO{C}OLS}
13 Seeds consumed by extinct primates with the close of biggest peace offering (11) APPEASEMENT {AP{PEAS}EMEN}{b...sT}
16 Reeked of hunting ground? Have surgery (2,5,3,5) GO UNDER THE KNIFE*
19 Delay disrupted trade in army allowance (11) RETARDATION {R{TRADE*}ATION}
24 Really faint flare fired from pistol (4,5) VERY LIGHT [DD] (Addendum - {VERY}{LIGHT} - See comments)
25 Performer stripping sides from plant (5) ACTOR fACTORy
26 True lassis regularly used herb (5) TULSI {TrUe+LaSsIs}

27 Implement perhaps Friday party policy (9) MANDOLINE {MAN}{DO}{LINE}

DOWN
1   Clutch back end of cigarette lighter (5) BARGE {GRAB<=}{c...tE}
2   Point out horse (5) PINTO*

3   Classic bear on a road (8) STANDARD {STAND}{A}{RD}
4   Come forward, raising heartless Punch and Judy (4,2) ?T?P ?P (Addendum - STEP UP PUPpETS<= - See comments)
5   Withdraw quietly and do penance in church monument (8) CENOTAPH {P}{ATONE}<= in{CH}

6   In component of bathometer (2,4) AT HOME [T]
7   Island nation’s singles infiltrating subcontinent (9) INDONESIA {IND{ONES}IA}

8   Spooner’s mentioned harsh accommodation (9) BEDSITTER (~said bitter)
14 Unfinished tomb in stone compound (9) AGGRAVATE {AG{GRAVe}ATE}
15 Born absolutely to embrace female creature (9) BUTTERFLY {B}{UTTER{F}LY}

17 Notice Georgia in capital sporting event (4,4) ROAD GAME {RO{AD}{GA}ME}
18 Is fair trial impossible in this court? (8) KANGAROO [CD]
20 Earl in trouble over papers placed differently (6) RELAID {EARL*}{ID}
21 Purpose of ointment to exclude old and married (6) INTENT oINTmENT
22 Distressed sir leaves artistic storage area (5) ATTIC ArTisTIC
23 Anguish good for bishop, in short (5) GRIEF (-b+g)GRIEF (Correction - BRIEF (-g+b)BRIEF - See comments)

Reference List
100 = C, Quietly = P, Born = B, Female = F, Papers = ID, Old = O, Married = M, Good = G, Bishop = B