More likely, this is Obama's equivalent of Reagan's "We do not negotiate with terrorists"... just a lie for the cameras.
He doesn't want a trial for this guy. He just wants the issue to go away. The security damage has already been done, if you believe the bit about Snowden having distribute d encrypted copies of the documents, etc...
It would also undermine everything Snowden has done so far, so unless they tortured him or he is completely insane I seriously doubt he did that.
Realistically, the data in there probably isn't all that time-sensitive. It's not like we're in an active war with Russia and Snowden took copies of an upcoming US invasion plan with him there. In that case, two things would matter: if the Russians had the data, and whether they had cracked the encryption. However, in this case, the data Snowden has is useful as a general "What do they know" exercise. This is data that will remain interesting for the Russians and Chinese even if it takes months to crack. So, at this point, it is a problem for the US if the Russians are just in possession of it, even encrypted. It's just another bargaining chip that they have.
If Snowden is in Russia, and he has encrypted data, and he himself knows the decryption key... then I wouldn't have boundless confidence in a 29-year-old's ability to resist the persuasive power of the Russian 'deep security state' to obtain his keys.
Given amnesia- and compliance-inducing drugs, Snowden might not even be sure he's given up the goods... just wake up one morning a bit more groggy and 'jetlagged' than usual.
I think it's fairly obvious Obama used "29 year old" to imply immaturity and chip away at his credibility thereby. (esp since he is 30 now, surprising how different "30 year old hacker" sounds than "29 year old hacker"..)
Holding other things constant, an older Snowden would be relatively more likely to have...
• ...known what kinds of tricks and pressures (including non-consensual drugged interrogation) he might be subjected to
• ...received official training, initial or refresher, in resistance
• ...planned well for worst-case outcomes, like not being able to stay above-ground in law-and-order Hong Kong, but rather winding up at the mercy of Russia
I don't know for sure whether in general, older or younger people are better at resisting interrogation. I suspect the 'dark arts' for coercing compliance have evolved over a longer term than any person's lifetime, and prey on any one person's limited experience, so I tend to think they'll work better with the younger... but it's an interesting question.
I do suspect an older person would be more likely to protect himself beforehand, for example by not traveling with the most truly US-interest-damaging data, or encrypting data with a better cipher, or even encrypting data in a way he couldn't, alone under coercion, decrypt.
The problem with this approach is that it doesn't buy Obama much with the people he's disappointed on this issue. But it does get the matter out of the public eye and prevent additional embarrassment.
China already has whatever they wanted from snowden,
Russia already has whatever they wanted from snowden,
Encrypted copies of his data are in the hands of probably dozens of journalists and ambasadors,
and the story is already on the news...
The best example would be for him to be disappeared. Let his encrypted secrets come to light, so it's obvious that he's either dead or getting tortured somewhere, and that the American government simply doesn't care about diplomatic niceties when it comes to silencing whistleblowers. That would be a lesson to the wary.
Fighting with Russia for him would just draw more attention to it.
However, at least here in Germany this is unthinkable, given the number of human rights violations we still have to fix here in our own country.
Snowden might be in Russia for some time.