Across
Hans about to change his ways? (9)
Moon having ghostly appearance gets one in a state (5)
Sat on throne, dictator's not exactly hailed (7)
I haven't cracked this one yet — but Fifteensquared have:
Homophone (dictator’s = said out loud) of RAINED (not exactly hailed: raindrops rather than hailstones, but it seems a rather weak definition).
17d
(and 17 Down) Right rubbish home office decor (7,2,6)
Part of network where one travelling to work needs other end of platform (8)
I haven't cracked this one yet — but Fifteensquared have:
COM [m] UTER (one travelling to work), with the second M replaced by P , which is the other end of the word P[latfor]M.
Terms describing large spheres (6)
I haven't cracked this one yet — but Fifteensquared have:
WORDS (terms) containing (describing) L (abbreviation for large). World = sphere = the extent of one’s interest or influence.
One receiving hidden signals making inroads with traitors? (10,5)
Characters within cell revolutionised record number of countries (6)
I haven't cracked this one yet — but Fifteensquared have:
Inner letters (characters within . . .) of [n] EURO [n] (a nerve cell), then EP (abbreviation for extended-play record) reversed (revolutionised). A group of countries = a number of countries.
A bit of drama ahead of Italian family's latest project (8)
I haven't cracked this one yet — but Fifteensquared have:
ACT IV (the fourth section of a play = a bit of a drama) + IT (abbreviation for Italian) + last letter (latest) of [famil] Y .
Partner after divorce papers, say? (7)
I haven't cracked this one yet — but Fifteensquared have:
EX (short for ex-wife or ex-husband = partner after a divorce) + PRESS (newspapers). As in to express one’s opinion.
Has more than ridiculous amounts (7)
Leads from random encounter could change entire investigation (5)
Tackle with great speed finishes off uneven game for City (9)
I haven't cracked this one yet — but Fifteensquared have:
MACH I (in aerodynamics, a speed equivalent to the speed of sound = great speed) + last letters (finishes) of [uneve] N [gam] E [fo] R [cit] Y . Tackle = mechanical equipment for lifting heavy weights.
Down
A quick haircut outside university hall (6)
I haven't cracked this one yet — but Fifteensquared have:
A TRIM (a quick basic haircut) around U (abbreviation for university). Latin-derived term for an open public space within a larger building.
South African philosophy club untucked trousers (6)
Shakes from extremely stylish milk dispensers (8)
I haven't cracked this one yet — but Fifteensquared have:
Outer letters (extremes) of S [tylis] H , then UDDERS (the part of a cow from which we obtain milk, though “dispensers” seems an odd way of putting it).
I don't believe that last gift's totally unwrapped (2,2)
I haven't cracked this one yet — but Fifteensquared have:
[l] AS [t] [g] IF [t] with all the outer letters removed (totally unwrapped). A disdainful expression, indicating that what’s just been suggested is impossible; used in much the same way as “pigs might fly”.
At last, it's do or die – failing another way out (4,4)
I haven't cracked this one yet — but Fifteensquared have:
Anagram (failing) of the last letter of [it’] S + DO OR DIE . The adjacent “do or” in the anagram fodder makes this a bit too obvious, I think.
Hunk and date aboard toboggan wrapped up warm (8)
I haven't cracked this one yet — but Fifteensquared have:
WAD (hunk?) + D (abbreviation for date), contained in (aboard) SLED (toboggan). “Wad” and “hunk” can both mean “lump”, but I’m not sure they’re interchangeable; “wad” usually means something loose (such as hay or rags) pushed together into a tight bundle, and “hunk” means a rough piece cut off a larger solid mass (such as bread or cheese).
One's stoned, having foolish date on company time (7)
I haven't cracked this one yet — but Fifteensquared have:
APR I (abbreviation for April 1 = All Fool’s Day = foolish date) + CO (abbreviation for company) + T (abbreviation for time). A fruit with a stone.
Calls from capsized sailor not getting an answer (5)
I haven't cracked this one yet — but Fifteensquared have:
SE [a] MAN (sailor), without the first A (abbreviation for answer), reversed (capsized = upside down in a down clue). As in “she calls him Fred”.
US tax collectors slashing American rate for high-flying area (8)
I haven't cracked this one yet — but Fifteensquared have:
IRS (abbreviation for Internal Revenue Service = the US federal tax organisation), inserted into (slashing) A (abbreviation for American) + PACE (rate).
Famous backing singers somehow mess up holding note (8)
I haven't cracked this one yet — but Fifteensquared have:
Anagram (somehow) of MESS UP , containing RE (a note in the musical sol-fa scale, as in do-re-mi). “Backing singers” is a little unfair: the group was originally “The Supremes” without a named lead singer, then briefly “Diana Ross and the Supremes”, and continued under their original name after Ross left.
See 11 Across
Poem about end of journey on ship taking years (7)
I haven't cracked this one yet — but Fifteensquared have:
ODE (poem), around the end letter of [journe] Y + SS (abbreviation for steamship, originally “screw steamer” from its screw propeller), then Y (abbreviation for years). Clue-as-definition (&lit): Homer’s ancient Greek epic poem about Odysseus’s ten-year sea journey home (with many adventures and interruptions) after the Trojan War.
Ruler from space periodically visited meteors (5)
I haven't cracked this one yet — but Fifteensquared have:
EM (a wide space between characters in printing) + alternate letters (periodically visited) of [m] E [t] E [o] R [s]. Also spelled emir or amir: Arabic term for a monarch or other authority figure.
Understand tenor's committed to one night in Paris (6)
I haven't cracked this one yet — but Fifteensquared have:
T (abbreviation for tenor in vocal music), inserted into (committed to) I (one in Roman numerals) + NUIT (French word for night, so “night in Paris”). To understand by instinct rather than from knowledge or evidence.
Perhaps something Methuselah said scanned (6)
I haven't cracked this one yet — but Fifteensquared have:
Methuselah (Noah’s grandfather in the Old Testament, said to have lived a very long life) might have said I’M AGED . No comment on whether our crossword setter of the same name might feel the same way. Image, as a verb = scan = make an image of something, especially for medical diagnostics.
Wrestler's a little too muscular to be flipped over (4)
Type letters or click words in the clue