"I read that accumulo supports cell level security, and hbase doesn't. Is this true?"
Both systems support cell-level security; however, I would say that Accumulo's is a more "battle-hardened" implementation. I'm not aware of any case studies behind comparing the two implementations.
"and secondly accumulo supports multiple data sources ingestion better
and hbase one source such as one web site. is it true? in what ways?"
No, I don't know in what way this would be possible. Both systems can ingest data from a variety of sources. This sounds like something was taken out of context.
"can someone share any accumulo case studies?"
http://accumulo.apache.org/papers/ has some content, http://www.pdl.cmu.edu/SDI/2013/slides/big_graph_nsa_rd_2013_56002v1.pdf, https://arxiv.org/abs/1406.4923, and http://accumulo.apache.org/papers/accumulo-benchmarking-2.1.pdf are each interesting. This talk from PHEMI by Russ Weeks is also particularly nice http://accumulosummit.com/program/talks/preventing-bugs-how-phemi-put-accumulo-to-work-in-the-field/
"Can accumulo be used with full support and rest of hadoop ecosystem?"
In short, "yes", but this is subjective due to what you consider the "rest of hadoop ecosystem" and what degree of integration you're expecting. The same goes for HBase. As for HDP, yes, both HBase and Accumulo are fully supported as Tim pointed out already. I would suggest you ask more pointed questions if you have specific concerns.