I enjoy predicting what the achievements will require just by the name and picture. With the heavy update, the picture's file name had descriptive text, but this time we're not so lucky. So here we go with my guesses:
I'm Bat Man:
Probably just grinding Bat kills. I'd guess 100 kills, unless this is the epic grind, then I'd say 1.000
Hitting someone with a ball from the Sandman when you can't see them.
Cap the intel without being hit, or without hitting anyone else. Probably requires both.
Out of the Park:
I have no idea for this one. Hitting someone out of a level, so they fall to their death? It'd require a new piece of equipment for the Alternate Primary weapon, since as of now, the Scout can't do knockback.
Something about double jumping, obviously. I can't imagine them awarding an achievement for merely double jumping a lot, but that's all I got with this picture.
I'm guessing stunning someone with the Sandman, then killing them before they recover.
Race for the Pennant:
Be the first person in a game of CTF to grab the Intel.
Retire the Runner:
Drink 100 sodas?
Capture three intels in a single life.
Set the Table:
Be the first on your team to get to the CP, identical to Vanguard.
In a map like Granary, your team captures all the points without losing any.
This looks like the good-old "scout cap" to me: capture the second point within a few seconds of your team capturing the first point.
Stun someone for the maximum possible stun duration.
The Big Hurt:
Kill someone entirely with baseballs? I was assuming that the baseball only did stunning and no damage, so maybe reduce someone from full health to zero while they're still stunned.
Kill someone underwater, on the ground, and in the air, in one life.
Capture three CPs in a single life?
I got nothing. Steal three Intels in a single game?
A Year to Remember:
Capture a total of 365 CPs.
Dodge 1.000 shots with the Bonk! Energy Drink.
Bat someone to death whilst you are both in mid-air.
Batting the Doctor:
Bat 10 doctors to death.
Return a baseball with your own baseball bat.
Kill Five people while holding the Intel.
Block the Plate:
Defend 50 CPs.
Stun 25 people with the Sandman while they are next to the cart.
Unless this has something to do with the alternate shotgun, I'm guessing this entails killing someone while a drowsy scout.
I'm hoping this isn't an achievement rewarding Scouts for taking Teleports, although that would be funny. I'm betting it involves destroying teleporter entrances/exits. Let's say 25.
Doctoring the Ball:
Stunning people with the Sandman while being healed by a medic? That seems super-lame.
Dodgers 1, Giants 0:
Bat a heavy to death whilst he's eating a Sandvitch.
Use a second jump to avoid falling to death.
Be the first person to kill someone in a round.
First Blood, Part 2:
Be the first person to kill someone in a round, but with a Bat.
Fall so far that you'd die if you didn't double jump.
Kill 50 people with the pistol.
If You Build It:
Wreck 25 engineer buildings.