This will be the greatest ever test for Monero to actually show itself. Obviously 625k is not that much money for some people but honestly for majority of hackers in the world that is incredible amount plus it is mainly white hacking as well. It is still not white hacking in the sense that it helps people, it doesn't help anyone and it actually hurts monero users, but it is hacking legally because IRS is the one that requested it, so basically you are doing something not "nice" but doing it for the government, which is why I believe it could be considered white hat. At the end of the day if nobody can do it, that will make Monero loved even more, it would be incredibly rewarding to not get hacked even with 625k on the line, but if they do end up getting cracked, I wouldn't really be upset with them neither, it is totally understandable, it is a lot of money and great minds will be working towards it.
If monero doesn't get cracked, it's def going to the moon lol