Portable generator? Or is this a fixed location for a residence? 9 KW is about 50 amps, hence the 50 amp breaker for the generator feeder. For my money I'd regroup your critical loads into a new panel making sure you don't overload the generator. I'd then use one transfer switch in the feed to that panel so that when a power loss occurs, your critical loads are switched from your utility to the generator. Your first option sounds a lot like this and is the one I'd go with.