Integrated Bussing solution
by Kegler

Twenty words gain either an O or an X, as indicated by the center entry, HUGS AND KISSES.
The extra letters are shown in brackets in the clue parsings, and in gray in the grid.

Integrated Bussing solution grid

Across
1UNF{O}(bUNs) + D)ED
8MASS (2 defs)
11NILe
13I + HOP
14MACHines{O}
15ARE(N)AS
16ROMANS (MANORS anag)
17LA{X}(I + T)Y
20WEE + D
22DE(MU)R (RED rev)
25TON + S (NOT rev)
26FO,{X}ES
27HUGS AND KISSES
30OV{O}ID (hidden)
32EME(ND)ER
36TE{X}AS (odd letters)
37DISC{O} (hidden)
39femA{X}LE
40DETOUR (TOURED anag)
41PREMI{X}ES (PREMISE, move the S)
43BR{O}AD (1st letters)
44L(OR)E
45MA(I)N
46A + S(Y)LUM
47TED (2 defs)
48SIN + G
Down
1UNTRUTH (HURT NUT anag)
2FL(A + M)ING{O}
3{O}S + CARS
4UGH (HUG anag)
5NO{O}SE ("KNOWS" hom)
6EARL (REAL anag)
7D(R)EAD + S
8M(IN){X}ESs
9A + H + A
10SP(R)Y
12L + ATE{X}
18TUBE + R + CU + LINe
19SOU (hidden)
21D + EKES
23MUS + E (SUM rev)
24REST + {O}RING
26FAD + ED
28NE{X}T (TEN rev)
29IN + DE{X}ED
31VE{X}E(R)S
33MAR + MOT (TOM + RAM rev)
34MA + MBA
35ALL + {O}Y
38ITEMS (SMITE anag)
41PAL (1st letters)
42ELM (MEL anag)