Can I Still Use PT9 with a PT11 License?

We have been running PT9 on a 2007 Macbook Pro at our home studio for some time. We just purchased a brand new iMac computer that will become our primary machine, and want to install PT11 on it. We have a free upgrade to PT11 waiting for us since our version of PT9 was the academic version. However, in order to redeem our license for PT11 on our iLok, we must "surrender" our PT9 license. We want to keep PT9 installed on our old computer since we still have some unfinished sessions on there, and also as a backup in case there are any hiccups with 11. But we want to be able to use PT11 on the new machine as well. So my question is, if we surrender our 9 license to get the 11 license, would it still be possible to use PT9 on our old machine?