Facings issues with Camera 0.2.0 and flutter 0.9.0 - dart

Question

I am trying to setup camera 0.2.0 with flutter 0.9.0 in order to make app cater non AndroidX mobiles but I am facing weird error. I was not getting this error in the latest stable version of flutter.
My main.dart code file is
import 'package:flutter/material.dart';
import './app/alert_on_crises.dart';
import 'package:flutter/services.dart';
import 'package:camera/camera.dart';
import 'dart:async';
List<CameraDescription> cameras;
Future<void> main() async {
// SystemChrome.setPreferredOrientations([
// DeviceOrientation.portraitUp,
// DeviceOrientation.portraitDown
// ]);
cameras = await availableCameras();
runApp(new AlertOnCrises(cameras));
}
And app logs when it starts
E/flutter (12582):
[ERROR:topaz/lib/tonic/logging/dart_error.cc(16)]
Unhandled exception:
E/flutter (12582): NoSuchMethodError: Attempted to use type
'CameraDescription' as a function. Since types do not define a method
'call', this is not possible. Did you intend to call the
CameraDescription constructor and forget the 'new' operator?
E/flutter (12582): Receiver: CameraDescription
E/flutter (12582): Tried calling: CameraDescription(lensDirection:
Instance of 'CameraLensDirection', name: "0")
E/flutter (12582): #0 Object.noSuchMethod (dart:core-
patch/dart:core/object_patch.dart:46)
E/flutter (12582): #1 availableCameras.
(package:camera/camera.dart:55)
E/flutter (12582): #2 MappedListIterable.elementAt
(dart:_internal/iterable.dart:414)
E/flutter (12582): #3 ListIterable.toList
(dart:_internal/iterable.dart:219)
E/flutter (12582): #4 availableCameras (package:camera/camera.dart:59)
E/flutter (12582):
E/flutter (12582): #5 main
(file:///home/nishant/alert_on_crises/lib/main.dart:13)
E/flutter (12582):
E/flutter (12582): #6 _startIsolate. (dart:isolate-
patch/dart:isolate/isolate_patch.dart:279)
E/flutter (12582): #7 _RawReceivePortImpl._handleMessage
(dart:isolate-
patch/dart:isolate/isolate_patch.dart:165)
Syncing files to device vivo 1723... 5.8s
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An Observatory debugger and profiler on vivo 1723 is available at:
http://127.0.0.1:8101/
For a more detailed help message, press "h". To quit, press "q".