I had to consciously get out of my "comfort zone" and tell myself "it is *not* significantly more risky." In fact, consider that the more *time* you are on the bike, the more chances there are for something to happen, so by reducing the time, you are reducing the risk.
Your reactions are much better than you think they are... mine are actually pretty sucky - but they're good enough for 15-20 mph on ar egular basis.
You also might *have* to go that fast some times... so you want to be able to do it.
If the sight of the number is slowing you donw, take the 'puter off. If it *feels* too fast, keep it on and make yourself take it up to ... whatever you can stand. It's doubly hard because being nervous affects those reactions too... so school yourself to relax and, yes, LEAN INTO things.
Think about how fast people on motorcycles go for millions of miles without crashing.
And look for that part of you that *enjoys* the breeze and feeling **strong.**
Also, here's teh GUILT TRIP MOTIVATION if that's what will work: you're not doing any of us a favor going 9 mph. Drivers tend to *think* we all move slower than we do... and you're perpetuating that... so the driver that judges whether or not s/he can make that turn in front of you might misjudge the next person... so inch it up to 11, okay?? (or, if they don't 'cause they're better educated, then you're not doing what's expected and that's more likely to cause an accident, too.) [Okay, the reality is there are lots of otehr riders out there going slower *and* faster than that... but it helps motivate me...]