TL;DR

Not much, really. A shutter speed of 11ms, indoor, with low light, is a difficult situation even for a professional camera.

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Longer

Note: my English is limited, and I reply with just the information I could find about the Raspicam.

I suppose you are making the usual mistake of confounding frame rate (fps) with shutter speed; they are similar, yet unrelated.

Shutter speed is the length of time the camera sensor is exposed to light: the longer light is allowed to enter the camera and hit the sensor inside, the brighter the final image will be; e.g. a shutter speed of 10ms means that the shutter is open for 10ms and that the sensor receives light for that amount of time.

Frame rate is, instead, the rate at which the camera records the frames: without going too much into detail, 90fps means that every 1/90 of a second the camera takes whatever signal is on the sensor and generates a new frame. There is no duration here: what is there is there.

So, if you set your shutter speed to 11ms it means that your shutter opens, the sensor receives light for 11 ms, then the shutter closes, and so on. And sincerely, at 1/90 of shutter speed indoor in poor light condition without a flash you can't hope much even from good gear, much less from a toy camera like the Raspicam.

So what can you do, in the end?

Well...it depends.

The Raspi has separate settings for frame rate and shutter speed. So, you can keep the 90fps if you really need it and change the shutter speed to try to achieve something if the conditions allow for it. Theory states that your shutter speed should be twice the frame rate, so for a frame rate of 90fps (1/90) your shutter speed should be 5.5ms (1/180); this is a good rule of thumb, but you can ignore it if the results fit your needs and, for example, try to do the opposite. I seriously doubt you'll end up with something good, but yet, there's no harm in trying.