It's a general rule in almost every airport that, to meet anyone during transit flight, you need to go to arrivals area; for that you need to obtain transit visa.
Because you have more than 12 hours of layover, you can apply for transit visa on arrival or Transit without visa:
TWOV facility is offered only to Indian Sub Continental Countries citizens.
TWOV cannot be given to visitors who do not possess visa from 3rd country of destination as follows:
Australia; New Zealand, United States of America, Japan, China,
Taiwan, South Korea
TWOV facility cannot exceed more than 120 hours (5 days).
TWOV facility is not available at entry point other than Kuala Lumpur International Airport (KLIA) and Kuala Lumpur International Airport 2 (KLIA2)
TWOV cannot be offered to passenger sponsored by airlines other than Malaysia Airlines, Air Asia and Malindo Air. At present only these 3 airlines have agreed and accepted all terms and conditions imposed by the Malaysian Government.
TWOV cannot be given to visitors who do not meet the following requirement:
Valid national passport or internationally recognized travel
document; Travel documents valid for more than six (6) months from
the date of entry; A return ticket to country of origin; Not listed
in the Immigration Department’s suspected list.
There will be no extension of TWOV facility.
Permanent resident and long term pass holder are not bound to any of the TWOV regulations and condition stipulated above.
TWOV will be issued free of charge at the Visa on Arrival counter at the immigration clearance upon arrival.
Indian Sub Continent countries listed are Sri Lanka, India, Bangadesh, Pakistan on the klia2 info page.
Leaving you belongings there might not be ideal, as you wouldn't want to risk getting your student visa.
