I'm a bit confused. You mention 'job' and 'client,' so I assume you're a professional, but your question indicates that you aren't a licensed electrician. Doesn't that kind of work need to be done by a licensed electrian, to pass inspection? And what do the codes in your area say about the number of fixtures/plugs that can be on a single circuit—wouldn't nine more be too many, and require a separate circuit?
As far as determining the current load goes, you would have to know where every plug and fixture is located on that particular circuit, and what the uses are. With that, you can find out without a tool just how much draw there could be. For example, if a refrigerator is on the circuit, you would have to 'test' it while the motor was running, not idle, anyway, so you might as well pull the fridge out and check the amperage/watts/hp on the motor. Same with t.v.s, radios, and even light fixtures. Also, you need to figure in things like a vacuum cleaner being plugged in and used, or a hair dryer—both of which draw a lot of amperage. And what wire is available in the circuits that now exist—12/2 or 14/2? Wouldn't you be better off just running a new circuit? If the circuit breaker box doesn't have any room, you might be able to replace single breakers with those spiffy double mini-units.
But, again, I would hesitate to do the wiring myself, in your current (forgive the pun) situation.
Best of luck.
Nolo illigitamati carborundum