The errant passes are partially because of low awareness. I see no point in upgrading it to above 85 though unless other stats are already high.
What's his other throws like and what's your USER accuracy sliders at? That'll make a HUGE difference.
I like to get mine up to 70. It's a cheap upgrade, and I personally notice passes being placed in better spots when I use the left stick to direct the pass.
In my online league, I have a rookie QB with
AWR 65, THP 93, SAC 86, MAC 75, DAC 70, PAC 68 and I have sliders at 15 user accuracy I believe. This QB doesn't consistently miss passes like it sounds like yours does, but obviously isn't going 20-20. In my solo league I play at like 4 USER acc and passes are all over the place. I'll have to find out what his awareness is at, he's 88 OVR though.
About clutch, I've never purchased that for a developing QB. MAYBE for a QB like Luck, Newton, etc since they are already established.