The new Closed Test article for Update 15.9 introduces no fewer than six new ships to the game. For the upcoming European cruiser branch, Dragon at Tier IV and Kralj Petar I at Tier V are entering testing first.
The four higher-tier newcomers are considerably more intriguing, though: Honolulu at Tier VII, Akagi at Tier VIII, Ōta at Tier IX, and Rodina at Tier X.
As always with announcements like these, one important reminder: all values are still work in progress and may change during testing.
Akagi: two kinds of squadron instead of the same attack loop
Akagi is likely to bring one of the most interesting concepts among the new arrivals.
The Japanese Tier VIII aircraft carrier combines regular torpedo bombers and HE skip bombers with tactical torpedo bomber and HE dive bomber squadrons.

The two squadron types fill different roles. The tactical squadrons offer greater damage potential but have comparatively low aircraft HP.
The regular squadrons are more robust in use, but are limited by small reserves and slow restoration.
Wargaming therefore appears to be deliberately testing a carrier that puts greater emphasis on squadron management itself. Instead of constantly repeating the same attack loop, the challenge is likely to be combining the different squadron types sensibly.
If this concept largely survives testing, Akagi could be particularly interesting to CV players who want a little more decision-making depth between individual attack waves.
Ōta: twelve 100-mm guns with a four-second reload
Things get even more unusual with Ōta.
The Japanese Tier IX cruiser receives twelve 100-mm guns with a four-second reload. Her HE shells have 30 mm of base penetration, putting her potential DPM roughly in territory more commonly associated with Kitakaze.

She also gets an enhanced Engine Boost, Exhaust Smoke, and Submarine Surveillance.
Ōta has to go without Hydro, however.
On paper, this makes for an aggressive flanking cruiser that could become extremely unpleasant from inside her smoke. At the same time, her low durability is likely to punish poor positioning quite consistently.
The combination of smoke, mobility, and this rate of fire in particular will probably be one of the points where Wargaming needs to watch actual battle performance very closely during testing.
Honolulu: Helena with more tools
Honolulu takes a much more conventional route at Tier VII.
With 15 × 152-mm guns, the basic idea initially looks very similar to Helena. Honolulu pays for her extras with shorter range and less DPM, however.

In return, she gets a much broader consumable package with Smoke, Hydro, and Repair Party, as well as good concealment.
That makes her look less like a pure gun cruiser and more like a cautious, flexible Helena variant.
Around caps, island positions, and in situations where her own smoke allows a retreat or an additional firing position, she could feel considerably more comfortable to play.
Rodina and the new European cruisers
With Rodina at Tier X, another high-tier Premium newcomer is also in testing.
Meanwhile, the upcoming European cruiser branch continues to grow. Dragon at Tier IV and Kralj Petar I at Tier V join the branch's already known test ships.

That makes Update 15.9 unusually extensive for a Closed Test. What is interesting is less the sheer number of new ships than the range of concepts being tested.
Akagi and Ōta in particular do not look like mere variants of existing ships; their mechanics are intended to give them genuinely distinct playstyles.
Kill Counter for the new Black Friday ships
Alongside the new test ships, Update 15.9 is also testing a small but rather neat feature: a Kill Counter on the permanent Black Friday camouflages of the four new B ships.
The counter is visible on the ship and records the player's own kills.
Kills are counted separately for Random, Ranked, and Co-op. The counter is even intended to update during the battle itself.
Anyone who does not want it can disable the display in the camouflage options.
The feature is being tested on Hornet B, Incheon B, Victoria B, and Flandre B.
That gives the black variants at least a little more individuality, rather than simply painting the same ships black again and putting them back in the shop window.
Conclusion
Akagi and Ōta are currently the two ships worth watching from this test.
Akagi's mix of regular and tactical squadrons could finally produce another CV where choosing and rotating squadrons accounts for a greater part of the actual gameplay.
Ōta, meanwhile, is a candidate for extremely unpleasant flanking positions with her twelve rapid-firing 100-mm guns, Exhaust Smoke, and enhanced Engine Boost. That could be particularly interesting for Ranked and smaller competitive formats, provided the combination of smoke and DPM is not substantially cut back during testing.
For all six ships, however, the same rule applies: Closed Test means work in progress. These values are not yet a basis for planning resources or purchases.