Awesome, that's great news! Glad you're enjoying it, because I know that combat in particular was something you really hated for a long while there.
Thanks for the report on the repeatable missions, I've fixed that for the next version. What an oversight!
For the planetcracker, there's a couple of ways to have that happen:
1. After a certain amount of time has passed (I think it's 4 hours now in the next version), if the Acutians REALLY have a high animosity towards another race, but are not at war with them yet, then they will tend to start a planetcracker instead of a direct attack. Also, they have to have a spare uncolonized moon. The whole planetcracker thing was really super over-common recently, like the gas giant ignition is now, and we've been working to dial that back and thus make it more meaningful (for a while there it would literally happen about every 10 minutes, then get called off, then happen again, etc, heh).
2. Alternatively, you can spend a bunch of Credit with the Actutians as a political deal to get them to do it for you. You have to be dealing with a CEO from one of these industries: Mining, Finance, Insurance, Entertainment, or Defense. Defense is the cheapest option in terms of cost to you. They still have to have a spare moon, and you have to have at least 90 influence with them as well. You get to pick the target.
If a CEO of the sort you want is not available, then work on constructing buildings for the industry you want. If the power of that industry is ascendant at the next industry quorum, then one of the CEOs from that industry will oust one of the CEOs that are not favorable to planetcracking.