A voltage divider is used to reduce voltage, so that is not what you want. Further, as you noted, they are better suited for low-level signals rather than high power circuitry due to the power loss.
I'd look at some sort of switching boost regulator. I'm not terribly familiar with solar panels but there may be specific types of regulators designed to handle the varying output from the panel. Most boost regulators can handle a range of input voltage, but I'm just saying that solar is a specific application with specific characteristics that may need to be taken into account.
At any rate, 7.5V @ 8A input is 60W and 36V @ 2A output is 72W, so that's not going to happen, we can't get something for nothing. Plus, conversion circuitry will be less than 100% efficient. Check around, but 80% - 90% is probably more realistic. So that'd be 48-54W out, or 1.3 to 1.5A at 36V. Ohm's Law is your friend 