I just came from Best Buy and they have a few Motorola phones that work with Boost (CDMA compatible). To name a couple, there's: Motorola - MOTO G (4th Generation) 4G LTE with 16GB Memory/32GB Memory;
and emory/64GB Memory
You may check all Motorola phones on their website here: click on each phone to check the description to be sure it is compatible.
CDMA phones that work on Sprint work on Boost. In the past, Boost wouldn't unlock phones. The law now requires unlocking. Since this phone comes unlocked, there's no reason why Boost can't accept it. Boost sells a Moto G4, in fact.
They don't let you bring it if it's unlocked. I have a Moto G1 that was originally a Boost phone which I bought from Boost and used on their network for a few years. I got it unlocked to try another carrier on the Sprint network. I didn't like that carrier much and wanted to bring it back to Boost but Boost doesn't allow it back even though both carriers are the Sprint Network. It's not the phone itself it's Boost's policy. Probably because they want you to buy a new phone from them.