To play devil's advocate for a second, I think it's (arguably) reasonable tactics to raise more in late position with big hands (I mean KK and AA primarily, but QQ, AKs, and maybe JJ also). Reason being, you get a bigger pot going if/when someone calls you, and it's easier to get stacks in. Additionally, you might get people 3-betting you light or playing back at you post-flop specifically because they think your raise size is weak - it's a built-in level against some players. Where 99 comes into it is range balancing - if you do this with strong hands and are playing with regs, you need to occasionally do it with weaker hands, and also occasionally not do it with the strong ones.

However - I have no idea if that relates to hero's thinking here at all. Maybe he just hates playing 99, or maybe he always opens for 5x on the button. In which case I'd have to agree with nuts and mcat. You'll get more action and more profits opening for a standard amount.