There is a lot of speculation about this topic, and I have a valid theory about it. Before I say it, lets point out the questions at hand.
1. Why would Kairi receive the exact same keyblade Aqua obtained from meeting her in BBS?
2. Why does Riku summon the Destiny Place?
Let me start off by stating my theory, which basically answers question 1, but is not true until proven true. Aqua's basic connection to Kairi. Aqua placed a spell on Kairi, so whenever she was caught in darkness, light would save her. Kairi received the Keyblade from Riku when they were surrounded by Heartless (darkness). The Keyblade is of the Realm of Light. Put one and one together and what do you get? Aqua's spell protecting Kairi by letting her receive her Keyblade, and leading her from darkness. This is my theory.
Now, let me clear up exactly why Riku summoned the Destiny Place. There is a general answer.
The general answer: Kairi is not an official Keyblade wielder. She had not had been given a Keyblade until now, thus wouldn't hold the power to summon one until given one. Riku is an official keyblade wielder, thus was the only person that was able to give her a Keyblade at that point in time.
There is a lot of speculation about this topic, and I have a valid theory about it. Before I say it, lets point out the questions at hand.
1. Why would Kairi receive the exact same keyblade Aqua obtained from meeting her in BBS?
2. Why does Riku summon the Destiny Place?
Let me start off by stating my theory, which basically answers question 1, but is not true until proven true. Aqua's basic connection to Kairi. Aqua placed a spell on Kairi, so whenever she was caught in darkness, light would save her. Kairi received the Keyblade from Riku when they were surrounded by Heartless (darkness). The Keyblade is of the Realm of Light. Put one and one together and what do you get? Aqua's spell protecting Kairi by letting her receive her Keyblade, and leading her from darkness. This is my theory.
Now, let me clear up exactly why Riku summoned the Destiny Place. There is a general answer.
The general answer: Kairi is not an official Keyblade wielder. She had not had been given a Keyblade until now, thus wouldn't hold the power to summon one until given one. Riku is an official keyblade wielder, thus was the only person that was able to give her a Keyblade at that point in time.