The California Driver's Manual describes a carpool lane as a special freeway lane only for buses and/or carpools. You may use a carpool, or high occupancy, lane or on ramp if your vehicle carries the minimum number of people required for that carpool lane or if you drive a low-emission vehicle displaying a special DMV-issued decal. Motorcycle riders may also use designated carpool lanes, unless otherwise posted.
Driving in the carpool lane without the minimum number of people or entering/exiting the lane when there are solid lines can get you a citation by law enforcement. Each time you are convicted of a moving traffic law violation in California, the court notifies the Department of Vehicle and the conviction is placed on your CA driver license record.
DMV points are attached to certain types of moving violations. You did not state what the exact violation was that you were ticketed for. From the violation list available at www.dmv.ca.gov/dl/vioptct.htm it would appear there could be a couple of 1 point violations that you might have received.
There is 1 violation point for entering or exiting a high-occupancy lane at an incorrect time (21655.8). This means driving over double lines instead of entering/exiting in the areas designated or where there is a single broken line.
Another type of ticket you might have received is improper lane use. This is also a 1 point violation. To find out for certain if the type of citation you received is assigned points, check the violation list site mentioned above or contact the CA DMV.