Let's think about this for a moment, shall we? We have an action (Bush's rhetoric) and we have a phenomenon (people believing Saddam was involved with the 9/11 attacks). We have a hypothesis that the action resulted in the phenomenon. What's the basis for this conclusion? Well, nothing, really. First off, we have NO evidence for what led people to believe what they believed. Bush isn't the only source of information for anyone, and people often come to conclusions even without being told of an answer. Secondly, the hypothesis is basically that Bush created a belief in something that, by the article's own admission, wasn't what he actually said - so we've got to assume that all those people didn't just believe Bush, but they all either misunderstood or extrapolated from what he said, AND that they all adopted a belief based on this misunderstanding or extrapolation, despite Bush having never said it. Is that possible? Maybe. Is there evidence that happened? No.
But it's even worse than that. Let's assume, to be generous, that what Bush says IS that formative of opinions (not something I actually believe is the case). Did he form this particular opinion by his rhetoric? Again, we can't tell from this article. Why? Because we don't know what public opinion was BEFORE he started talking about Iraq. If the numbers started out higher, then isn't it just as possible that the ACTUAL statements from the Bush administration (which included explicit statements that we had no evidence Saddam had a hand in 9/11) actually decreased the percentage of people who thought Saddam was involved in 9/11? We're missing the crucial bit of information, even with the most generous interpretation I can give you.
So, what's the real numbers? I don't know. It's tough because different polls don't all ask the same question, so comparing numbers at different times isn't straightforward. But IIRC, a poll done on 9/13/2001 showed that 78% of the US thought that it was at least likely Saddam was involved in the attacks - that's a slightly broader classification, of course, but it's entirely possible that the number who thought he WAS involved still started out higher than the 45% being cited here.
In other words, all you've got are wild assumptions and rampant speculation. What you do NOT have is proof of any lie, or even a deception.
So, basically, you admit they may (they did) have tried to deceive, but if people believed it, it was probably from some other source? Pretty convoluted defense, if you ask me.
The simplest explanation is that Americans by and large believed their leaders. The fact that Bush and company did deliberately try to deceive is undeniable. See my post above.