Across
9
Constitutional capital of Afghanistan twice (two) 14 (9)
10
As some boats flew, though not originally (5)
12
Help out, or fail to help children's author (2,4,3)
13
Empire behind supporter (7)
14
Capital of Lebanon twice bombed, returned to former glory? (7)
17
Capital of Norway twice 14 for birds (5)
19
Sign letter for the auditor? (3)
20
Block hiding other blocks (5)
21
Tango, then go for twist (7)
22
Get hot man — capital! (7)
24
One capital of France, twice 14, covering items (9)
26
Swollen stem: squash in retrospect (5)
28
Capital of Latvia twice 14 sought prize (5)
29
Briefly stir cream perhaps into strong coffee, creation of barista (4,5)
Down
1
Reportedly, break up exchange (4)
2
Able to bend, one held in place (6)
3
One capital of Spain twice 14, arranged by chance (10)
5
In the beginning, coat user shivering (2,6)
6
Capital getting up in the morning (4)
7
Time capital of Germany twice 14, more than 23, roughly speaking? (8)
8
Every second gone and rift opening underground (4)
13
Anything to eat ends in small hole for small predator (5)
15
Capital I would secure to invest in coffee (10)
16
Conveyed Theodore Roosevelt's letter opener? (5)
18
Eastern books on article in window (8)
19
Leave sign for musicians hosting upcoming meetings (5,3)
22
Again, relocate a US capital (6)
23
14, build new capital (6)
25
Considered material (4)
27
Bird, tail by the ear? (4)