Again here not sure what our line should be? Shove, raise fold or fold?
This is an area I gotta work on as I never know what to do when I get dealt medium hands in early position at FT.

[converted_hand][hand_history]Poker Stars, $3.19 Buy-in (800/1,600 blinds, 75 ante) No Limit Hold'em Tournament, 5 Players
Poker Tools Powered By Holdem Manager - The Ultimate Poker Software Suite. View Hand #37199006

BTN: 12,305 (7.7 bb)
SB: 11,851 (7.4 bb)
BB: 16,754 (10.5 bb)
Hero (MP): 14,655 (9.2 bb)
CO: 11,935 (7.5 bb)

Preflop: Hero is MP with 8 A
Hero?

Stacks is pretty even amongst you remaining players, no ubershorties who is destined to go out next and secure you a money jump.

5 handed and 9 BB this is a pretty clear shove from my point of view. What earns you money in sit and goes long term is top two finishes, wich is a big argument for shoving in these kind of spots.

Short version: Jam this.

TL;DR version:

At this point in a 45 man the average bubble factor is 1.72 - that usually means we don't want to tangle with anyone.

To illustrate this, I'm going to cheat and change your hand so everyone has equal stacks of 13500, because I think the general point this hand illustrates is more interesting.

Everyone has equity of 2598.4 cents. If a player grabs another player's stack and adds it to their own, the player eliminated gets fifth place prize of 1291 cents (they lost 1307.4 of equity) - the player who doubles his stack now has 3360 cents of equity (he gains 761.6 of equity) with the other three players gaining the missing 545.8 (181.9 each) as their benefit from laddering - their stacks are now worth 2780.3. The bubble factor of 1.72 (to one) describes the "odds against" we are fighting when we flip, we need to "bet" 1.72 of our equity for every dollar of equity we win (the dead money of the chip odds does help offset this) - so it becomes a game of chicken where the person who gets the stack in first wins.

Open jamming under chipEV (Nash Calculator).

Hero 26.1%, 22+ A2s+ A7o+ K8s+ KTo+ Q8s+ QTo+ J8s+ JTo T8s+ 98s 87s
CO 11.6%, 44+ A8s+ A9o+ KQs
BU 11.6%, 44+ A8s+ A9o+ KQs
SB 14.5%, 33+ A7s+ A8o+ KJs+ KQo
BB 20.7%, 22+ A2s+ A5o+ KTs+ KJo+ QJs

compare with:

Open jamming under 45 man payouts.

Hero 25.3%, 88+ 66 A2s+ A8o+ A5o-A3o K4s+ KTo+ Q9s+ QTo+ J9s+ JTo T9s
Called by
CO 2.6%, TT+ AKs
BU 4.7%, TT+ AQs+ AQo+
SB 5.4%, 99+ AJs+ AQo+
BB 6.3%, 99+ AJs+ AJo+

note that they can only call with premiums so we can still jam almost as wide as before as we pick up the dead money often enough when we get the last bet in.

If we analyse it as a raise/shove/fold game under these payout conditions we can only open maybe 16-17%, get jammed on by 13%-15% ranges by our opponents (our min-raise gets through half the time) and we call their jams with about our top 6% because even getting such good chip-odds (something like 1.4 to one depending on who jams) we can only call with premiums. The result is that our raise-folding range can't be very wide either, around 10%.

The interesting thing is, if this was happening at the 400/800/50 level and everyone had 16.9BBs rather than 8.4 BBs it's pretty similar.

You would be able to open jam

Hero 19.2%, TT+ A2s+ A9o+ A5o-A3o K9s+ K6s KTo+ QTs+ QJo JTs
called by:
CO 1.8%, JJ+
BU 2.6%, TT+ AKs
SB 2.6%, TT+ AKs
BB 4.2%, 99+ AQs+ AKo

note that when you strengthen your range from 25% to 19%, it's hard for them to find hands that crush your range enough to take the risk of calling, so their calling ranges shrink and you don't have to go any further to compensate for the dead money being halved.

In the raise/shove/fold game with 16.9 BB we would be able to open about 18-19%, we'd get jammed on by ranges of about 13-16% and with our worsened pot odds we could call only TT+/AK for 3.47% (or also AQs against jams from the blinds). So again we should just open-jam 16.9 BBs rather than mess about.

Basically, the best strategy in thermonuclear war is be the one who presses the red button first and that applies to these situations too Don't mess about pressing the yellow button, just press the red one straight away! That particularly applies in this situation where you cover most of the other players - you have a red button and they only have yellow or orange ones: here is Nash calculator's results for the actual stack sizes

Hero 29.4%, 22+ A2s+ A8o+ A5o-A2o K3s+ KTo+ Q8s+ QTo+ J8s+ JTo T9s
called by
CO 4.7%, TT+ AQs+ AQo+
BU 4.7%, TT+ AQs+ AQo+
SB 6.3%, 99+ AJs+ AJo+
BB 7.1%, 88+ ATs+ AJo+

you can jam even wider compared to even stacks as you are not risking elimination against most players but you are threatening it against them (though what's going on with the equities is not as binary as that sounds, we are still pressing an orangey-red button in relation to the BB).

Apart from all the above, if you open A8s and get flatted, under what circumstances are you willing to go to the felt post-flop?

The trouble with what Gilmour writes above is that "most money at the top" is also an argument for calling all-ins and flipping but that's disastrous in this situation.

Thank you for that long analysis, very helpful