I’m not sure that this is a good idea. Futures markets on things like assassinations have always run the risk of incentivizing people to do things that they shouldn’t, and this is similar.

Ukraine probably has a military plan in place to hit specific targets. You want people to target the targets judged to be optimal. If someone in the Ukrainian military can make money by making such a bet and then targeting the target that they have bet on, there is now an incentive separating their interests from that of the state.

Additionally, depending upon whether the betting information is made public (and whether that information, even if not made public, is properly secured), if someone bets using insider information, it may leak target information ahead of time, which may be detrimental to the Ukrainian state. Russia will have nation-state intelligence agency levels of capability in going after things in the war like strategic air targets.