Body movement
FIFA09 has far superior animations in basically any aspect I can think of. They are very evenly balanced in terms of pace, and nothing really stands out as being superhuman/not possible in real life). Foot planting for the most part is really good, and you can see a players foot really being "anchored" when it hits the pitch. Even just a bit of sliding completely ruins the illusion, because it looks completely wrong from real life.
Also FIFA09 has so much more nuance than PES09, such as teammates gradually going form full sprinting to jogging to walking to standing still, without any noticeable "steps".
The way players behave on the field
I have to give this to FIFA09 aswell. I've never been good at judging tactics or such, but PES09 seems pretty far removed from reality in terms of how you can pingpong through defences and such. PES09 usually still has some defensive line issues, and it feels disorganised in an unrealistic way for me. FIFA09, just from looking at it, strikes me as looking more like a real game would. Again, tactics and such aren't my strong side.
The actual gameplay
FIFA09 wins, hands down, in all technical aspects, and "controllability" aspects. Manual galore, actual analog sticks, etc etc.
But there are several things I would change for FIFA10.
For one, players are able to Control certain loose balls too quickly and with too much control. It seems like too often they are able to make split-second moves to control a ball, unrealistically.
Also, overall I would say that the speed and pace at which the players execute movements needs more variety. For example, there isn't really a way to get a player into a sort of "alert" or "quick-feet" mode when dribbling. Generally they feel too relaxed and slow to react to certain moves which in real life require split-second timing.
Basically, when I in real life would have been able to anticipate a defender making a stab tackle, and very quickly execute a heel roll of the ball to the side, in FIFA that "anticipation" aspect is nonexistant. You either have "execute dribble" or don't do anything.
One way to solve this would be to use the manual aspect of the FIFA LT trigger, which is used for the "dribble mode" in the game. The more you depress the button, the higher alert the player would be in, the quicker he would move his feet (to always have a foot ready to manipulate the ball). The "downside" would be that the player wouldn't be able to move fast forward, since running fast means that you need to do longer moves with the feet. Basically, the more you depress LT, the quicker "access" you would have to the players feet for a dribble or feint move, at the sacrifice of movement speed.
Players like Ronaldo and Messi though would be allowed a higher rate of movement when fully in the "reaction mode", since they can execute very quick touches on the ball even when their legs are also busy just propelling them forward.
This would be a great way to make the dribbling aspect more realistic, because the "quick feet" or "coiled up and anticipating to execute a dribble" aspect is lacking, and it takes away some of the fun and realism from both the trick stick dribbling aswell as the normal dribble and movement pattern.
Also the general movement pattern of the FIFA09 LT "Slow-dribble" mode should be designed more like the PES09 R2 dribble mode, which has the player manipulating the ball very nicely and realistically.
Also, the LT dribble mode needs more nuance and control in terms of how far the player will manipulate the ball in a direction.
In PES, if you hold R2 and move it to the player's side, he will start manipulating the ball in that directon, but if you very quickly change directions, he will immediately abort his previous move and start moving to move the ball in the other direction. So you can move the ball a short distance, like 30 cm, in one direction with the players right-foot instep, and then change direction and have the player manipulate the ball in the other direction with the outside instead.
FIFA09 in this department has alot less nuance and control, and the player is more "shoving" the ball quite violently (in comparison to PES which is slower but more controlled and composed)in a direction rather than controlling it in a way where he can quickly make changes.
If FIFA09 had an analog LT dribble mode, you could, by adjusting how much the button is depressed, how much urgency the player will have in the ball manipulations, and if you have maximum urgency, he will be quick to make sudden changes to how the ball is manipulated.
Which AI is better
Overall FIFA09. Just playing Be A Pro gives a hint as to which AI is better at reading the game in a realistic way. PES misses to many obvious pass opportunities and makes silly mistakes for my liking (though PES2009 is better than PES2008 in this respect).
Ball physics
Overall I like FIFA09 as the more realistic of the 2. Apart from some weird curl implementation when mishitting backspin shots, shooting normal backspin shots, aswell as during freekicks, FIFA09 has the more realistic ball behavior.
PES did surprise me positively, but some of the aspects of FIFA09 still aren't really there.
And as far as deflections and such are concerned, FIFA09 is in a different league entirely.
Graphics
FIFA09 for me. PES09 has some awesome lighting, but it is till a bit too bare-bones for me. FIFA09 is a bit more "flashy" in terms of lighting and coloring, but I prefer it. Also while PES has added some new more detailed lighting aspects, like the "sunset" lighting, and overall higher resolution to it, FIFA09 wins with the ball being able to cast shadows on goalkeepers as it flies past, players self-shadowing with arms and such in a very detailed-looking way, etc. Kits seem better in PES, but higher resolution in FIFA.
And for me, FIFA09 is just so much more "cozy" and warm to play a day match in. The contrast between sunlight and shadow, just the general appearance appeals to me. The pitch in FIFA09 looks like a proper pitch, whereas in PES it looks like a texture. I probably prefer the PES 3D grass effect more for closeups, but FIFA09 has improved from 08 atleast.
Cutscene animations in PES are better though for me. Also FIFA's camera movements during the interactive celebrations are pretty poor, they should have just used the normal ingame camera the whole tine rather than suddenly making the camera "float" around to show the celebration. Not really what you see on TV...
Another neat touch for PES is the way players will start celebrating before the ball crosses the goal line, which eliminates that old-gen bit where your player will just wait motionless or move like normal even though it is clear that the ball will go in. The game now detects if a shot or such will be a certain goal (ie not savable by the goalkeeper or defenders) and your player doesn't need to stand around waiting for the ball to actually cross the line.