1)
Here it says that "Kol ha'Aretz" wanted to see Shlomo to hear his Chachmah. In Divrei ha'Yamim II, 9:22 it says "Kol Malchei ha'Aretz"!
1.
Malbim (Divrei ha'Yamim II, 9:22): There it explains what it says here.
2)
Why does it mention Shlomo's Chachmah amidst discussing his wealth?
1.
'Rashi' (Divrei ha'Yamim II, 9:22): This teaches that "Nasati Lecha Lev Chacham" (Melachim I, 3:12) was fulfilled
2.
Malbim (23-25): This was the reason for his wealth! Everyone came to hear his Chachmah, and the custom is to bring a gift when coming to see a great king.
