Hope this helps. First the good news:

1) "...is there an actual small-ish bulb in the headlights that screws out/pops out- or?..."

Answer: Yes. It's a #9004, and held in place by a collar that twists for release.

2) "...is there a way to adjust the projection of the headlight beam?..."

Answer: Yes. There are two adjusters for each headlight -- these stick out the back (toward the engine) from the headlight housing, two adjusters on each headlight. For advice on how much to adjust (up or down, or sideways), consult www.danielsternlighting.com

Now, I'm sorry, the bad news:

3) "...are there brighter bulbs such as halogens that can be used?..."

Answer: You already have halogens, albeit somewhat low wattage, and I really don't suggest higher wattage halogens for at least two reasons:

a) You've got a relay behind your dash's center vents that's already prone to burning out its connector, and any increase in bulb wattage may make that closer to a sure thing. Anytime you want to upgrade to higher wattage bulbs, I urge you to consider parallel wiring using relays (again see www.danielsternlighting.com), which reduces current through Volvo's wiring to a minimum.

b) You've got really lousy optics with your original headlights -- that's the problem, rather than not having a bright-enough bulb inside. More light from a higher wattage bulb will just cause more glare, objections from oncoming drivers (despite your adjustment), and will not improve your own vision, I'm afraid, simply because your headlights are not focusing the light in a useful pattern. Blame the antiquated DOT of the U.S. government (in the late '80s-early '90's) for this -- subsequently they bended to pressure and allowed improved lighting, as found in Europe, but it was too late for the production of our old 240's. Your only recourse for better lighting is to get Euroheadlights (the lamps issued on the cars in Europe) -- I bought Euroheadlights for both of my '93's, and they are wonderful but they're expensive, I'm afraid.