’Tis the Season solution
by Kegler

In eleven cases, two letters are put into one square; read left to right and top to bottom, the paired letters spell out HAPPY HOLIDAYS EVERYBODY.

’Tis the Season solution grid

Across
1COMP + RISES
6SISAL (hidden)
9H + AND + I + CAP + PER
10MAY + HEM
11PRO(LAP)SE (PAL rev)
12IDEOLOGY (DOYLE I GO anag)
13I + SO + PATH + Y
15IT'S + Y
16SP(R)AY
18CASHMERE (SEARCH ME anag)
23LAC(ROSS)E
24CU + R(T)AIL
26CAR(E)S
27A[NNI/d]VERSARY (INN rev)
28BO(TnT)OM
29TROGLODYTE (TROY GOT LED anag)
Down
1C(SH)ARPS
2MU(D + HO)LES
3RECAP (rev)
4SUPPLiES + T
5SORDIDLY (DRY SOLID anag)
6SYMBOLISM (rev hidden)
7S + KY + HO + OKS
8LIME(Y)S
14P(LAY)POS + SUM (POPS anag)
17P(ACK)RAT (TARP rev)
18CO(SECA)N + T (ACES rev)
19SECONDO (NO COEDS anag)
20R(H)APS + OD + Y (rev)
21PLACE + BO
22GLO(RY)BE
25RE(V + E)AL