2A: DELAY (double definition)
7A: CODS ("returned" DOC + S)
13A: THRUSH (beneaTH RUSHer)
15A: NIS (SIN "left")
23A: TOO (homophone of "two")
24A: EPEE (P from partnership inside EEE)
25A: LICE (LI + C + E from European)
27A: NORI (IRON "back")
28A: OGRESS (EGRESS with E changed to November's 2nd letter, O)
33A: EVE (firsts of Eastern Voters Elected)
34A: ORDER (BORDERS minus edge letters)

1D: PLACARD ("climbing" ALP + CARD)
2D: DREAR (D from greed + REAR)
3D: LAMB (BALM anagram)
4D: YORE (YO + RE)
5D: LIP (LP around I)
6D: IDS (initial letters of International Drivers' School)
7D: CONSTANT (odd letters of CrOoNiSsTrAyNoTe)
8D: ON (last two letters of LION)
9D: SCAR (SR, abbr. for senor, around CA)
11D: LATE (LA + "outskirts" of THE = TE)
12D: LEISURE (RULES IN anagram)
14D: HOBO (HO + BO)
15D: NEWER (N with EWER below it)
16D: BAILIFF (BIFF around AIL)
18D: DECOR (CO in DER = RED running upward)
19D: DOUSE (MOUSE with M replaced with D from dry)
20D: SINGE (SING + E from the)
21D: OPINE (IN POE anagram)
22D: DEBASE (SEABED anagram)
26D: EGGED (E.G. + G.E.D.)
29D: RIVE (RIVER without end letter)
30D: EVER (VEER anagram)
31D: SNOB (pariS NOBility)

It can be inferred that the three long unclued entries spell out:

PLACEONSCRABBLE

ANDFINDBESTWORD

FORGIVENLETTERS

Following the first part of those instructions gets you this board:

The remaining pieces of information, DOTHREE, SCOOREM, and ORDEREM, are all seven letters long, the size of Scrabble racks. You can interpret them to mean: play these three racks (finding the highest-scoring word for each), and then order the words you created by the scores of the plays. The best plays are:

BOTHERED (15 * 3 + 11 * 3 + 50 = 128)
COMPOSER (8 * 3 + 14 * 3 * 3 + 50 + 5 * 3 = 215)
HEDONISM (15 + 8 = 23)

Ordering these gives a new cryptic clue, HEDONISM BOTHERED COMPOSER. This solves to SONDHEIM. Stephen Sondheim was the person who brought cryptic crossword puzzles to the US.

Thanks to Scrabulizer for the boards.