Using the VOIP phone, just dial out as you normally would without needing to dial "9".  If you are calling another number at MIT, you can dial the whole number or just the last 5 digits.  For international calls, again, no need to dial "9", first dial "011" + "Country code" + "phone number".  Here is a website you can use to find Country codes: https://www.howtocallabroad.com/