I've purchased 2 brand new Strats in 2009, one an American Standard with recomended strings from the specs page on the Fender website of
3250L Super Bullets gauges .009 to .046. The other is an American Deluxe with recomended strings 3250L Super Bullets (9 to 42). As far as I can tell 9 to 46 strings would be 3250LR. What is the correct string gauge for an American Standard Strat?

Welcome.

In the 'real world' (meaning, sidestepping Fender's marketing propaganda for you to use their strings or your guitar shall suffer), you can use pretty much any gauge and brand of electric guitar strings you want provided that the guitar is correctly set up for whichever set it is of your choosing.

_________________
You dig?

The correct diameters for 3250Ls are .09 - .042, and that is what came on my 09 Am Stdrd.

I had to switch from Fender strings, due to them breaking so much. Switched to D'addarios, and never had that problem again.

_________________
"I won't be wronged, I won't be insulted, I won't be laid a hand on. I don't do these things to other people, and I require the same from them."-John Wayne

Thicker strings can make for a tonal difference, and .008's give too thin a sound. Light gauge strings bend easier. I put Ernie Ball Super Slinkys on my Strat and like the sound. You can play around with it, trying different strings, different gauges.