Can I use any capacitor for a 2 phase AC motor?
Yes, you need a cap. The cap must be rated for the job. A 250VAC or better metal film cap will be needed.

The phase shift is never exactly 90 degrees but it does not have to be. The capacitance needed is roughly proportional to the size of the motor. If your cap is small you will still get starting torque but not very much. If your cap is too big, you get more starting torque but you increase no load current consumption and risk burning out the motor. Running torque does not change much with cap value.

If your load is "easy" like a fan you have a wide range of capacitance to work with. If your load is "hard" like a piston compressor you will have to get the cap right be ensuring that the motor starts under load. Under no load on the bench you could start with 10uF and take things from there.