That is correct.
Year round children aged 9 and under may wear costumes in the parks. The only time persons over the age of 9 can wear costumes are at special events like Mickey's Trick-Or-Treat Party this Halloween at DCA.
Halloween Time at the Disneyland Resort
Note: there are Australian, Spanish language and other versions of the Disneyland and WDW sites. DLR is down on the lower left hand corner.
Mickey's Trick-Or-Treat Party at Disney's California Adventure Park
They would let you into Disneyland with a costume on if it did not look much like a costume such as Indy style clothes and hat. Sorry to spoil your dream of dancing down Main Street in costume. Prices for AP start at $26 per person and up to 8 tickets per AP plus free parking for one vehicle. It last four hours and ends at 10:30 or 11:30 PM.Costume Information
All event attendees — including adults — may dress in their favorite Halloween costume and must follow these and other guidelines as determined solely by Disney:
- Costumes should be child-friendly and may not be obstructive, offensive or violent.
- Guests may wear masks. However, masks must not obstruct vision and eyes must be visible at all times.
- Guests who dress like Disney Characters may not pose for pictures or sign autographs for other Guests.
- Costumes should not drag on the ground.
- Costumes should not contain sharp objects, pointed objects or materials that may accidentally strike another Guest.
- Costumes should not contain any weapons which resemble or could easily be mistaken for an actual weapon.
- Guests of all ages may only wear costumes to the Disneyland® Resort Halloween event to which they have valid tickets. During normal Park operating hours, costumes are permitted only for Guests ages 9 and younger.
Guests who do not adhere to these guidelines may be refused entry into the event unless his or her costume can be modified to meet the above standards.
I am not sure what I will wear if anything but would love to go as a race car driver or the little old lady from Pasadena. A song from long ago that few will remember.