Alright, never made a Warlock character before, so please let me know if I am missing something painfully obvious.

I am creating a lvl 10 Warlock and the Table says that a lvl 10 Warlock should have 10 Spells Known, 2 Spell Slots, and Spell Slot Level of 5th.

I have 2 main questions. 1) In the Character Creator, I am unable to add any spells from the Warlock Spell List at a higher level than 1. So, I have access to Cantrips and 1-st Level spells only. At lvl 20, according to the Table, a Warlock should have 15 Spells Known. But, if you take out the duplicate of "Hideous Laughter" and "Tasha's Hideous Laughter", there are only 14 1st-Level spells. Hell, there are only 10 in the PHB. Where are the remaining spells coming from? 2) Why does the Warlock Spell List, in the PHB, go up to 9th-Level if you can only learn 1st-Level spells? 

Is this a bug, or am I missing something? Thanks for your help!

Refresh.

If you level up on the spell list tab it wont cache properly. Solution is: refresh. 

You'll then able to select spells higher than 1st.

Warlocks get 1st level spells and higher up to 5th level spells. After that you select 6th, 7th, 8th and 9 th level spells using the Mystic Arcanum feature which you will see on the Character Builder class tab when levelling up from 11th level onwards.

You should be able to learn spells up to level 5.  refresh the page.

The level 6-9 spells are for mystic arcanum (the warlock's version of high level slots).

[Edit]I should have refreshed. Cyb3r already said all this.

Thank you very much, that fixed it!