Shapeshift does not allow this, you can never go higher than your Alteration score in any attribute.
There has been quite a bit of talk on how to do Blue Mage from FF. A lot of said to either just wait to assign points until you see things from mobs, or to not use banes/boons until you see them.
Either way it is something that would take a lot of discussion with the GM beforehand so they can help you set it up. Swing by the discord and I’m sure some people can give you more input, I’m in the middle of traveling today or I might give more.
Another way to go would be alternate form.