Adobe is very good when you call them if ever you have an activation issue.
To the best of my memory you're allowed, just as with the full version, two activations. Please see the EULA to be sure: http://www.adobe.com/products/eulas/
One thing you should also know is that upgrades won't be at the academic price but at the full retail upgrade price if you know what I mean. The price will be the upgrade price normally payable by the retail customers. Academic software don't have upgrades because these courses normally finish within a year or so. for some students they need to buy another academic edition if they have to continue using the software in the subsequent years and assuming they want a newer vesion.