I just ran into a similar situation recently. I also work in IT and wanted something I could carry my laptop and/or iPad (lighter and easier to carry instead of my 13" Dell laptop these days), and I was looking at all sorts of messenger bags that had a compartment specifically for a concealed gun (unloaded of course) and could still lock and look classy for my business field,
I looked at Maxpedition since they had some good bags with dividers and velcro panels where a holster or gun strap could attach to. However, they were all really expensive and still had that 'tactical' feel & look to it, and I wanted something more subtle.
I then found the perfect laptop bag in one of our other offices sitting in storage, and it looked perfect. It was a smaller bag that had 2 separate laptop sections in it, so you could carry a laptop in either padded compartment. Plus, the zippers on both compartments were lockable, where they had padlock loops on them so when the zippers came together you could put a padlock around the overlapping loops (similar to how you lock a suitcase when traveling). My 13" laptop fit perfectly in there on one side. On the other side, my LC9 and a couple of mags fit in there perfectly since they're narrow & light, and don't make the bag bulge out at all. The only thing I changed was the shoulder strap to a better one, but that's it.
As somebody mentioned earlier, look into laptop-specific backpacks as they are usually lockable, padded, and aw more discreet looking.