8. Look at dance organ (7)
EYEBALL - organ (EYE), dance (BALL) - which nearly works - but, but with thanks to The Rotter - this works better - organ=eyeball from look at (EYE), dance (BALL).
9. Ugly dwarf’s charge for passage across river (5)
TROLL - charge for passage (TOLL - on a motorway or across a river bridge), across river (R).
10. Almost failing to start ahead of schedule (5)
EARLY - almost failing to start n(EARLY).
11. Mark of wound allowed to be red (7)
SCARLET - mark of wound (SCAR), allowed (LET).
12. Reverse one’s opinion to support railway infrastructure? (9)
BACKTRACK - support (BACK), railway infrastructure (TRACK).
14. Rodent sailor’s turned back (3)
RAT - sailor - tar - turned back (RAT).
16. Style of singing used in opera performances (3)
RAP - in ope(RA P)erformances. Seems very much not the done thing to actually incorporate rap into operas but if it hasn’t already been done, no doubt one day it will be.
18. I am dock worker material (9)
IMPORTANT - I am (IM), dock (PORT), worker (ANT).
21. Architect of plans boy wizard has left inside (7)
PLOTTER - boy wizard (POTTER) has left (L) inside. A ruse used by JK's Ministry of Magic to discredit young Harry. With 'troll' at 3ac I wondered about a theme but nothing else turned up.
22. Upset about time in shop (5)
STORE - upset (SORE) about time (T).
23. Quiet anger in part of the country (5)
SHIRE - quiet (SH), anger (IRE).
24. Fib about fermented honey drink being a non-alcoholic one (7)
LIMEADE - fine (LIE) about fermented honey drink (MEAD). Neither of these drinks appeal.
1. Concerning MP’s recall (8)
REMEMBER - concerning (RE), MP (MEMBER).
2. Measurement system encountered resistance with current Celsius (6)
METRIC - encountered (MET), resistance (R), current (I), Celsius (C). A little background on why current = I - the conventional symbol for current is I, which originates from the French phrase intensité du courant, (current intensity). ... The I symbol was used by André-Marie Ampère, after whom the unit of electric current is named, in formulating Ampère's force law (1820).
3. A lot that’s new in a month in spring (4)
MANY - new (N) in a month in spring (MAY).
4. Component of blood pressure lowered after some medical attention at first (6)
PLASMA - (P)ressure (L)owered (A)fter (S)ome (M)edical (A)ttention.
5. Fierce critic upset at racket (8)
ATTACKER - anagram (upset) of AT RACKET.
6. East London area, much favoured but not upper-class (6)
POPLAR - much favoured, properly said, would be 'popular' which may be shortened by some to 'poplar' as in 'e's right poplar, that geezer is'. I quite liked this but it was eclipsed for cod by 13dn. As brnchn points out an alternative (and, I think, correct) explanation is much favoured (POP)u(LAR) not upper class - without the 'U'. However, my explanation made me smile so I’ll stick with it.
7. Dreary set of rooms all on one level (4)
FLAT - double definition was my original take thinking that 'set of rooms' didn’t necessarily mean a flat. However, I bow to Sally below (and democracy - I’m outnumbered!) in upgrading this to a triple definition - dreary, set of rooms, all on one level.
13. Hit enter randomly to get something in the first cell here? (8)
THIRTEEN - anagram (randomly) of HIT ENTER. So far so good, but then I wondered if, as is common, I didn’t have the GK of a work of literature or a board game to understand the clue. Then lightning struck - the crossword is made up of cells and in the first cell of this answer is the number thirteen. COD.
15. Tons treated badly being in rags (8)
TATTERED - tons (T) and an anagram (badly) of TREATED.
17. In favour of healthy gain from trading (6)
PROFIT - in favour of (PRO), healthy (FIT).
19. Temporary release for good conduct of personal assistant’s function? (6)
PAROLE - personal assistant (PA), function (ROLE).
20. Obsessive geek is a girl in a thousand (6)
ANORAK - a girl (NORA) in a (A) and thousand (K). This was my second last in as I just didn’t see it for some time.
21. Fool’s under pressure to overtake (4)
PASS - fool (ASS) is under pressure (P).
22. Amount of money offered initially for wrestling (4)
SUMO - amount of money (SUM), (O)ffered.