That is how long you have to hook a person on a cold voicemail message according to this article on Salesopedia (my bold):
6 Interesting Sales Prospecting Statistics
1. In a recent survey 95% of salespeople said they can sell – they just need to get in front of more prospects.
2. Effective prospecting blends both marketing & selling.
3. Most salespeople HATE to prospect.
4. The best prospectors often close more business than the best salespeople.
5. Nearly 60% of high performing prospectors consider the phone ESSENTIAL to their prospecting success.
6. Decision makers listen to only 9 seconds of a “cold” voicemail before deciding to press delete?
Good points all of them. If you only have 9 sec., does it make sense to spend it stating your name and contact information? My thought is that it makes more sense to take an approach that buys you another 9 seconds. Whatever your approach, know that your window is smaller than you may have expected.