From my reading of the Marchand web page, the XM9 is stricly an electronic crossover, with no amp in it. It is one of the better electronic crossovers available. Their very best one is the one with the tubes, but it's alot of money. Marchand also makes amplifiers to go with their crossovers, but I don't know how they sound. You could use any amp you feel would suit your needs with the Marchand. I would highly recommend using a Marchand crossover. The XM9 is good and reasonably priced, as electronic crossovers go. If you can solder, they have an XM9 kit that's cheaper.
The Hypex, I know nothing about. Sorry.
The Hypex, I know nothing about. Sorry.