9.) Добро пожаловать в «Вася Пупкин и Ко». К сожалению, сейчас никого нет в офисе. Пожалуйста, оставьте ваше имя и номер телефона после сигнала. Мы вам перезвоним как можно скорее.
Consider for a moment how your phone is currently being answered. Professional courtesy is quite often not the standard for many college students. An abrupt "Yeah!" could be listed among the more courteous greetings. The more outrageous remarks will often buy you a major black mark in the professionalism category—even if it was your roommate answering your phone and acting crazy. A simple "This is ____" is always a pleasant change for a college student call. Make the change today, before the next (or first) employer phone call. If you have a landline, you should also encourage your roommate to do the same.

Context does matter here. If the caller would reasonably expect you to answer the phone (such as if they were calling a store or other place of business), an apology for not being able to get to the phone makes the most sense.
6.) Hola y bienvenido/a a John Doe AG, la agencia para muestras de productos. Lo sentimos, todas nuestras líneas están ocupadas en este momento. Por favor, inténtelo de nuevo más tarde o manténgase a la espera. Gracias. Su equipo de John Doe.