are not "compatible" with S57. They are a separate data format (although if you dig deep enough, the original CM93 shares some data definition principles with S57, but that's beyond the level of interest of most chart users).
That is to say - no, they can't be used with PolarView. Not likely to ever happen, as CMap/Jeppesen want *a lot* of money
for official CM93 SDK and, more importantly, that SDK will only work with legally obtained CM93 charts which are extremely expensive (their target market is large commercial
I wish there was a better answer, but there is no legal
way to use CM93 charts in software
that would be useful to individual navigators.