i would like to know if the SRX240H2, can support IDP license to be installed, and if is still possible to buy license to IDP to this plataform.
IDP is listed under "Features Supported in Junos OS 12.3X48-D75 on SRX240" where 12.3X48-D75 is the recommended version for a SRX240H2, so it is supported and you should be able to pusrchase a license:
Use the "Partner Locator" for finding a Juniper Reseller:
Hope the info helps.
The IDP license for the SRX240 is 'SRX240-IDP' which covers one year subscription. It's also available in a 3 year SKU: 'SRX240-IDP-3'.
If you have a cluster you need to purchase a subscription for both members.