I hate type IXs they're big hence easy to detect via active sonar and they turn veryyyy slo o o o o o o o o o o o o o o ow. Plus their underwater performance is poor(poor speed). And yeah almost forgot their dive time is miserable and they got noticed a lot further by her enemy hence you need to give longer underwater chase.
No wonder about your career results with type IXs
I prefer type VIIB/C they're fast)even faster with upgraded engine albeit with the cost in range), small enough to avoid active sonar(especially with sonar coating) and they're agile(fast dive time, turn faster). It's perfect
