I know Aikido doesnt teach as many strikes as other ma's but what strikes do you learn from aikido to stun or stagger you opponent? Punches? Kicks?

Perhaps Rupert Atkinson would be the best person to answer this as he has broad experience from a number of different styles of Aikido.

However, in my limited experience (i.e. limited to one aikido style/teacher), I would say that you may be better off learning striking from kempo/karate-jutsu.

I came from a striking art (TKD) first, and have studied striking (particularly kyusho-jutsu) from other arts, so I am probably not the best person to ask for advice on this, in the context of "pure" aikido.

I shall just say that (from my prior and other training), atemi with hand/foot and other anatomical weapons are inherent (but only insofar as "inferred") in aikido, although it is not in my humble experience, an overt thing.

I can only speak to my personal experience with Aikido. There are plenty of techniques where punches are used but primarily to tie up or distract your opponents energy (e.g., tsuki kotegaeshi and shomenuchi sankyo ura waza). They are also used as a check for your distance (katadori ikkyo through yonkyo and ushiro ryotedori ikkyo through yonkyo). We also have many variations of pushing underneath the chin with a palm heel that could easily be turned into strikes (and are strikes depending on how you apply them). There are also several variations of koyunage the seem to work the best for me when I have the feeling of punching my opponent in the head as I bring my arm around to face the same direction they are facing before I execute the throw. I miss their face by a good 2" but I could very easily turn this into a punch.

We also learn punches and tegatami (knife-hand) strikes but they seem to be based entirely up on our sword strikes.

As for kicks, I have never seen a kick as a response to an attack. We rarely do work on defense to kicks but are not fomrally trained in kicking (although many of us have other martial arts experience and know how to kick). My sensei explains that kicking, especially above the waste level destroys your balance. It's also very difficult to kick while wearing a hakama

Again, I'm sure there are other people with vastly more experience that I who can provide you with an explanation.

The main reason kicks aren't done in most aikido schools is because it is difficult to take the ukemi for it. But they are there, just that most people don't practice them. Your sensei is correct in saying that kicking above your waist destroys your balance. (Not directing this at anyone) But not teaching how to kick properly and how to defend against kicks, I think is a shame.