Can I use a capacitor which has 275v +-10% tolerance in a 9V circuit?
Any capacitor has four basic ratings:

1) Rated capacitance (in Farads, named after Micheal Faraday)

2) Manufacturing tolerance (in percentage of rated Farads)

3) Voltage (maximum) -- the highest voltage that can be applied without destroying the capacitor.

4) Temperature (primarily used only for electrolytic capacitors), typically this is related to (substantially below) the boiling point of the liquid electrolyte.

A further property of capacitors is 'leakage' -- but this is largely a function of the type of capacitor and is not a 'rating' within given types.

The combination of Farads and Voltage tells you how much electrical charge can be stored in the capacitor.  Higher voltage capacitors (of similar type) will be physically larger than lower voltage capacitors.