puzzle

 ACROSS

  1 Wander

  5 (Hey, you)

  9 Second attempt

 13 Belly button's region

 14 Something to flutter, informally

 15 Apple tablet

 16 Short words? (Note this answer's last 3 letters + ...)

 17 True geeky self (... this one's first 2)

 19 Constellation component

 20 Wine choice

 21 Monopoly pieces

 22 Person who has an app

 24 Narrowest of margins to win by

 25 Wellness center (Last 2 letters + ...)

 29 Velcro alternative (... first 4)

 33 Gene variant

 34 Wrath

 36 Pack (down)

 37 Egyptian boy king

 38 Word before "all" or "hours"

 40 Pro hoops league

 41 Biblical paradise

 43 Tic-___-toe

 44 Book lover

 47 Televised again (Last 3 letters + ...)

 49 Gamer's leg up (... first 2)

 51 Drubbing

 53 Median, e.g., briefly

 54 Houston MLB team

 57 Home of NOLA and KCMO

 58 Protected

 62 "Awesome," to the Ninja Turtles (Last 5 letters + ...)

 64 Like a peon's position (... first 3)

 65 Select All's menu

 66 Depend

 67 Blender setting

 68 Rational

 69 Settles IOUs

 70 River to the underworld

DOWN

  1 Cheer (for)

  2 Killer whale

  3 Habitually

  4 Unruly crowd

  5 Electrician's gripping tool

  6 Hourglass filler

  7 Figure with the format 123-45-6789: Abbr.

  8 Greek letter that symbolizes an angle

  9 Ice hockey enthusiast

 10 Heaviest Olympic sword

 11 "Rats!"

 12 Strangely, they can be even

 13 Hotel room fixtures

 18 Muddy up

 20 Prepare, as leftovers

 23 Mo. city near Ill.

 24 Fabled race loser

 25 One has nothing nice to say

 26 Manage to avoid

 27 Take in or let out

 28 Inning's beginning

 30 Like a positive attitude

 31 Plant firmly

 32 Word before "tire" or "change"

 35 List of mistakes

 39 Fiction's opposite

 42 Tell, as a story

 45 Letter before 8-Down

 46 Behaves badly

 48 Beginner, in gamer lingo

 50 College application components

 52 Seize illegally

 54 Unreturnable serves

 55 Scotch and ___

 56 Doppel-ganger, seemingly

 57 Like a terrible mood

 59 Off-kilter

 60 Show off at the gym

 61 What a peacock's tail spot resembles

 63 Teacher's org.

 64 Some records, for short

solution