Most tournaments evolve a meta which is defined during group stages. Teams come out with their best strategies to gain any advantage they can and then other teams study what works well and copy those picks.
The meta of TI9 was defined by OG who dominated games with carry Io, Alchemist, Enchantress, Magnus and other heroes who became first phase bans for most teams.
To understand why some heroes were picked and others ignored, it's important to understand the meta.
The most contested (combined picks and bans) heroes in the group stages were:
During the main event the most contested heroes were:
Other notable heroes were Shadow Demon, Chen, and Lifestealer.
What is similar about these heroes? Many of them have abilities which can influence team fights in significant ways by mitigating and amplifying damage.
These damage amplification and mitigation spells are sorely missing from Clockwerk and Ursa’s toolkit. They need to buy items such as Crimson Guard or Pipe of Insight and Ursa needs to buy items like Drums of Endurance, Blink Dagger, and Black King Bar before he can become effective in team fights. By the time they get these items other heroes will be out farming them.
Many of the most popular heroes at TI9 were heroes that can play multiple positions. This is very helpful during the draft because when you make a pick, you are forced into a certain play style. When you pick a hero that can play multiple positions, you force your enemies to take multiple roles into consideration and you can switch up your own play style later in the draft.
This is part of the reason Tiny, Enchantress, Ogre Magi, and Mirana were picked so often, they can play multiple positions and multiple roles.
An example of this would be game 3 of the upper bracket match of Evil Geniuses against OG. For OG’s last pick they chose Sand King for offlane and then Evil Geniuses countered this with Anti Mage. OG reacted masterfully to this and shifted JerAx, the position 4, to play Sand King, and then N0tail played Rubick as the position 5, all to allow OG.Ceb to play position 3 Enchantress. This switch up worked well and OG ended up winning the game.
Also in the same game Sumail played Mirana as mid, a hero that is usually played as support.
With Clockwerk, Ursa, and Keeper of the Light, you know which position they're going to be playing and what kind of game they want to play.
Keeper of the Light (kotl) is a hero that went through multiple changes to rework how this hero is meant to be played. Most notably Kotl’s ultimate ability changed from Spirit Form to Will-o-Wisp. Will-o-Wisp is an ultimate ability that causes enemies to be focused onto the Will-o-Wisp multiple times, incapacitating them. This spell was very powerful especially combined with refresher orb which allowed multiple instances of Will-o-Wisp to overlap, causing a very long area of effect stun.
The refresher orb effect was removed because it was too strong and ever since then Kotl has been ignored in professional games.
Kotl is also easily countered by popular carry heroes in the current meta such as Alchemist who has a high rate of attack speed and can get a Black King Bar 15 minutes into the game to kill the Will-o-Wisp before it can be effective in team fights. Lifestealer and Juggernaut are also heroes who can turn magic immune and kill the Will-o-Wisp so teams may have been hesitant to pick Kotl since popular heroes can counter his abilities easily.
Clockwerk’s playstyle did not fit too well in the TI9 meta compared to other heroes.
As a position 4 he needs to get up and close to the enemy to apply pressure. Other heroes like Elder Titan can instantly summon a spirit from a long distance and stomp, Earth Spirit can roll in from a far distance, and Mirana can shoot arrows from a very far distance.
As a position 3 he doesn’t have the same level of tankiness and ability to frontline like other popular offlane heroes. At TI9 offlane heroes were expected to build auras and sustain items which Clockwerk can’t do because he is the one who wants to initiate or counter initiate. He also lacks area of effect abilities to help him farm fast which many popular offlane heroes had like Tidehunter who can farm fast with his Anchor Smash ability.
Even though Ursa is a strong counter to the most contested hero at TI9 - Alchemist, teams may have decided that another hero is a better pick such as Lifestealer. Lifestealer has an ability that makes him magic immune, something that Ursa does not have. Ursa has his ultimate: Enrage which dispels debuffs on him but he can be kited easily.
Ursa is a strange hero to not be picked though because he’s a natural counter to not only Alchemist but Enchantress and Tidehunter as well. Enchantress has the ability to make enemies attack her slowly but Ursa can increase his attack speed greatly which makes him a counter. Tidehunter is tanky against most heroes due to his Kraken Shell ability but Ursa’s Fury Swipes ability cannot be dispelled by Kraken Shell.
He’s also one of the best heroes at killing Roshan who is always important in every high level game.
Perhaps because he does not offer much to his team unlike Sven who has a damage absorption spell and speed movement buff or Juggernaut who has a healing ward or Lifestealer with a built in magic immune ability. Ursa also lacks reliable tower damage which is a big problem for ending the game.