There should not be any issue to place Lord Jagananth on 9th place of Dasavatar, it is fully Shastra supported.
ସଂସାର ଜନଙ୍କୁ ସେହୁ ତାରିବା ନିମନ୍ତେ
ବଉଦ୍ଧ ରୁପରେ ବିଜେ ଛନ୍ତି ଜଗନ୍ନାଥେ ॥
ବଉଦ୍ଧ ରୁପରେ କଳି କଳାନ୍ତକ ସାଧି
କୁଟାନ୍ତକ ଦର୍ପଗଞ୍ଜ ଅଟ କୃପାନିଧି ॥
ଠାକୁରେ ବୋଇଲେ ରାଜା ହୋଇଲୁ କି ବାଇ,
କଳିଜୁଗେ ବସିବୁ ବଉଦ୍ଧ ରୁପ ହୋଇ ॥ (Deuḷa toḷā, Oriya Bhagabata)
ସମୁଦ୍ରେ ମେଲିଣ ପ୍ରଭୁ ଦିଅ ଦେବରାଜା,
କଳିଜୁଗେ ପାଇବେ ସେ ଦାରୁରୁପେ ପୁଜା ॥
The texts of the above prove that Jagannath was worshipped in Puri by the Oriyas as a form of Buddha from a long time. Jayadeva, in Gita Govinda also has described Buddha as one among the Dasavatara. Indrabhuti, the ancient king of Sambalaka (present Sambalpur district) of Oddiyan used to worship Jagannath as Buddha. This culture also influenced Buddhism in Nepal and Tibet. That is how Buddha is also worshipped as Jagannath in Nepal.
